forgot about the yml markup syntax (#14)

Author: tristanbes

README.md

@@ -82,7 +82,7 @@ you might instead try
 
 If you're using `shivammathur/setup-php` to setup PHP, `cs2pr` binary is shipped within:
 
-```
+```yml
 # ...
 jobs:
     phpstan-analysis:
@@ -103,7 +103,7 @@ jobs:
 
 If you're use a custom PHP installation, then your project needs to require `staabm/annotate-pull-request-from-checkstyle`
 
-```
+```yml
 # ...
 jobs:
     phpstan-analysis: