docs: use solc 0.8.21 in the examples

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/03-non-upgradeable-plugin/01-initialization.md

@@ -29,7 +29,7 @@ In this case, the compiler will force you to write a `constructor` function call
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {Plugin, IDAO} from '@aragon/osx/core/plugin/Plugin.sol';
 
@@ -57,7 +57,7 @@ To deploy our plugin via the [minimal clones pattern (ERC-1167)](https://eips.et
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PluginCloneable, IDAO} from '@aragon/osx/core/plugin/PluginCloneable.sol';
 

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/03-non-upgradeable-plugin/03-setup.md

@@ -41,7 +41,7 @@ Each `PluginSetup` contract is deployed only once and we will publish a separate
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PluginSetup, IPluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';
 import {SimpleAdmin} from './SimpleAdmin.sol';
@@ -227,7 +227,7 @@ Now, it's time to wrap up everything together. You should have a contract that l
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {Clones} from '@openzeppelin/contracts/proxy/Clones.sol';
 

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/03-non-upgradeable-plugin/index.md

@@ -85,7 +85,7 @@ Then, inside of the file, add the functionality:
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {Plugin, IDAO} from '@aragon/osx/core/plugin/Plugin.sol';
 
@@ -122,7 +122,7 @@ In the `prepareInstallation()` function here then, we will grant the `GREET_PERM
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';
 import {PermissionLib} from '@aragon/osx/core/permission/PermissionLib.sol';

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/04-upgradeable-plugin/01-initialization.md

@@ -14,7 +14,7 @@ This has to be called - otherwise, anyone else could call the plugin's initializ
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PluginUUPSUpgradeable, IDAO} '@aragon/osx/core/plugin/PluginUUPSUpgradeable.sol';
 

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/04-upgradeable-plugin/03-setup.md

@@ -12,7 +12,7 @@ Before building the Plugin Setup contract, make sure you have the logic for your
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {IDAO, PluginUUPSUpgradeable} from '@aragon/osx/core/plugin/PluginUUPSUpgradeable.sol';
 
@@ -53,7 +53,7 @@ Similarly, the `prepareUninstallation()` function takes in a `payload`.
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PermissionLib} from '@aragon/osx/core/permission/PermissionLib.sol';
 import {PluginSetup, IPluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/04-upgradeable-plugin/05-updating-versions.md

@@ -14,7 +14,7 @@ Firstly, you want to create the new build implementation contract the plugin sho
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {IDAO, PluginUUPSUpgradeable} from '@aragon/osx/core/plugin/PluginUUPSUpgradeable.sol';
 
@@ -61,7 +61,7 @@ In contrast to the original build 1, build 2 requires two input arguments: `uint
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PermissionLib} from '@aragon/osx/core/permission/PermissionLib.sol';
 import {PluginSetup, IPluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';
@@ -159,7 +159,7 @@ In this third build, for example, we are modifying the bytecode of the plugin.
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {IDAO, PluginUUPSUpgradeable} from '@aragon/osx/core/plugin/PluginUUPSUpgradeable.sol';
 
@@ -234,7 +234,7 @@ With each new build implementation, we will need to udate the Plugin Setup contr
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PermissionLib} from '@aragon/osx/core/permission/PermissionLib.sol';
 import {PluginSetup, IPluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';

packages/contracts/docs/developer-portal/02-how-to-guides/02-plugin-development/index.md

@@ -76,7 +76,7 @@ Inside the `GreeterPlugin.sol`, we want to:
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {Plugin, IDAO} from '@aragon/osx/core/plugin/Plugin.sol';
 
@@ -105,7 +105,7 @@ Inside the file, we'll add the `prepareInstallation` and `prepareUninstallation`
 
 ```solidity
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {PermissionLib} from '@aragon/osx/core/permission/PermissionLib.sol';
 import {PluginSetup} from '@aragon/osx/framework/plugin/setup/PluginSetup.sol';

packages/contracts/docs/developer-portal/index.md

@@ -37,7 +37,7 @@ Then, to use the contracts within your project, **import the contracts** through
 
 ```solidity title="MyCoolPlugin.sol"
 // SPDX-License-Identifier: AGPL-3.0-or-later
-pragma solidity 0.8.17;
+pragma solidity 0.8.21;
 
 import {Plugin, IDAO} from '@aragon/osx/core/plugin/Plugin.sol';