Add issue template for Gutenberg and or CoBlocks upgrade process

Adds a new template for the GitHub tracking issue, which is part of the process for upgrading Gutenberg and or CoBlocks on wpcom and its variations. 

More details and here: https://fieldguide.automattic.com/edit-focus/gutenberg-plugin-on-wpcom/ and https://fieldguide.automattic.com/edit-focus/coblocks/.

Discussion: https://a8c.slack.com/archives/C015AL3QL7M/p1592482937033700?thread_ts=1592479434.017400&cid=C015AL3QL7M

I encourage you to suggest changes/ improvements as well. I based it off an existing tracking issue (#43178) with only minimal changes. I also left the short IDs as is as examples.

More about GitHub issue templates: https://help.github.com/en/github/building-a-strong-community/about-issue-and-pull-request-templates

.github/ISSUE_TEMPLATE/coblocks-and-or-gutenberg-update-github-tracking-issue-template-.md

@@ -0,0 +1,39 @@
+---
+name: 'CoBlocks and or Gutenberg update GitHub Tracking Issue template '
+about: 'Template for Gutenberg/Coblocks plugin update process'' GitHub tracking issue,
+  more: '
+title: Update Gutenberg to v<version> and CoBlocks to v<version>
+labels: ''
+assignees: ''
+
+---
+
+We have installed Gutenberg `v<version>` and CoBlocks `v<version>` to edge sites for early feedback. 
+
+Feedback and bugs and the final activation of the plugins on wpcom will be tracked here, for anyone interested.
+
+Testing post: p7DVsv-8Oh-p2
+
+### Process
+
+* [x] Install version 8.3.0-rc.1. (D44703-code)
+* [x] Activate version 8.3.0-rc.1. on edge sites (D44704-code)
+* [x] Install version 8.3.0. (D44796-code)
+* [x] Activate version 8.3.0 on edge sites. (D44797-code)
+* [x] Activate 8.3.0 in production for all sites
+     - [x] Prepare diff (@pingwhoeverisresponsible) (D45045-code)
+     - [x] Commit/Deploy 
+* [x] Atomic (p9o2xV-UC-p2)
+* [x] Announce
+     - [x] public (https://wordpress.com/blog/2020/06/18/block-editor-updates/)
+     - [x] internal (p7DVsv-8Rd-p2)
+
+### Testing
+
+* Calypso E2E tests #43137
+* [x] Teamcity tests (D44704-code)
+
+### Bugs 🐛
+
+* [x] E2E: Block inserter menu not opening on openBlockInserterAndSearch(). https://github.com/Automattic/wp-calypso/issues/43179
+* (Not necessary for launch) Update default block categories for Automattic blocks. https://github.com/Automattic/wp-calypso/issues/43198

.github/ISSUE_TEMPLATE/coblocks-and-or-gutenberg-upgrade-github-tracking-issue-template-.md

@@ -0,0 +1,39 @@
+---
+name: 'CoBlocks and or Gutenberg upgrade GitHub Tracking Issue template '
+about: 'Template for Gutenberg/Coblocks plugin upgrade process'' GitHub tracking issue,
+  more: '
+title: Upgrade Gutenberg to v<version> and CoBlocks to v<version>
+labels: Plugins
+assignees: ''
+
+---
+
+We have installed Gutenberg `v<version>` and CoBlocks `v<version>` to edge sites for early feedback. 
+
+Feedback and bugs and the final activation of the plugins on wpcom will be tracked here, for anyone interested.
+
+Testing post: p7DVsv-8Oh-p2
+
+### Process
+
+* [x] Install version 8.3.0-rc.1. (D44703-code)
+* [x] Activate version 8.3.0-rc.1. on edge sites (D44704-code)
+* [x] Install version 8.3.0. (D44796-code)
+* [x] Activate version 8.3.0 on edge sites. (D44797-code)
+* [x] Activate 8.3.0 in production for all sites
+     - [x] Prepare diff (@pingwhoeverisresponsible) (D45045-code)
+     - [x] Commit/Deploy 
+* [x] Atomic (p9o2xV-UC-p2)
+* [x] Announce
+     - [x] public (https://wordpress.com/blog/2020/06/18/block-editor-updates/)
+     - [x] internal (p7DVsv-8Rd-p2)
+
+### Testing
+
+* Calypso E2E tests #43137
+* [x] Teamcity tests (D44704-code)
+
+### Bugs 🐛
+
+* [x] E2E: Block inserter menu not opening on openBlockInserterAndSearch(). https://github.com/Automattic/wp-calypso/issues/43179
+* (Not necessary for launch) Update default block categories for Automattic blocks. https://github.com/Automattic/wp-calypso/issues/43198