Improve readme syntax highlight

README.md

@@ -3,12 +3,12 @@
 A PHP HTTP client for the Keila newsletter API with Guzzle as single dependency.
 
 ### Install
-```
+```bash
 composer require dompie/keila-http-api
 ```
 
 ### How to use
-```
+```php
 require_once 'vendor/autoload.php';
 
 $httpClient = new \GuzzleHttp\Client();
@@ -30,7 +30,7 @@ Then you can pass the Guzzle ResponseInterface to your context.
 
 ### Response helper
 For testing purposes I've added also a KeilaResponse class to quickly access relevant items.
-```
+```php
 $response = \Dompie\KeilaApiClient\KeilaResponse::new($responseInterface);
 $response->hasData();
 $response->getDataItem(0); //First element from the data property
@@ -39,18 +39,18 @@ $response->getGuzzleResponse()->getStatusCode()
 
 
 ### ⚠️ Tests will trigger E-Mail sending. Use only with keila dev instance.
-```
+```bash
 cp phpunit.xml.dist phpunit.xml
 ```
 
 Put your Keila URI and Keila api key into phpunit.xml:
-```
+```xml
 <env name="KEILA_BASE_URI" value="http://keila.local:4000" force="true"/>
 <env name="KEILA_API_KEY" value="secret-api-key" force="true"/>
 ```
 
 #### Finally tests
-```
+```bash
 make test
 or
 XDEBUG_MODE=coverage make test-coverage