Add syntax highlighting to readme examples (#15)

Author: apmatthews

README.md

@@ -47,7 +47,7 @@ View your actions progress and logs by navigating to the "Actions" tab in your r
 
 ### Simple main.yml:
 
-```
+```yml
 name: Deploy to WP Engine
 on:
   push:
@@ -67,7 +67,7 @@ jobs:
 
 ### Extended main.yml
 
-```
+```yml
 name: Deploy to WP Engine
 on:
   push:
@@ -119,4 +119,4 @@ jobs:
 * [Defining environment variables in GitHub Actions](https://docs.github.com/en/actions/reference/environment-variables)
 * [Storing secrets in GitHub repositories](https://docs.github.com/en/actions/reference/encrypted-secrets)
 * It is recommended to leverage one of [WP Engine's .gitignore templates.](https://wpengine.com/support/git/#Add_gitignore)
-* This action excludes several files and directories from the deploy by default. See the [exclude.txt](https://github.com/wpengine/github-action-wpe-site-deploy/blob/main/exclude.txt) for reference.  
+* This action excludes several files and directories from the deploy by default. See the [exclude.txt](https://github.com/wpengine/github-action-wpe-site-deploy/blob/main/exclude.txt) for reference.