Updated github.ref to github.head_ref in CI workflows

Author: Reedyuk

.github/workflows/pull_request.yml

@@ -8,7 +8,7 @@ on:
     branches: [ master ]
 
 concurrency:
-  group: ci-pull-request-${{ github.ref }}
+  group: ci-pull-request-${{ github.head_ref }}
   cancel-in-progress: true
 
 jobs:

.github/workflows/pull_request_target.yml

@@ -5,7 +5,7 @@ on:
     branches: [ master ]
 
 concurrency:
-  group: ci-lint-api-check-${{ github.ref }}
+  group: ci-lint-api-check-${{ github.head_ref }}
   cancel-in-progress: true
 
 jobs: