Support reusable paths blocks via yaml anchors (#13)

* Add support for nested arrays of path expressions

* Remove pull_request trigger type options

Default value is fine: opened, synchronize, reopened

* Add CHANGELOG

* Update README

.github/workflows/pull-request-verification.yml

@@ -1,9 +1,6 @@
 name: "Pull Request Verification"
 on:
   pull_request:
-    types:
-      - opened
-      - synchronize
     branches:
       - master