Add license headers validation (#458)

* Add .licenserc.yaml file

* Fix license headers

* Add github action to check license headers

* Fix workflow

* Fix checkout path

* Rename workflow

* Add debug info

* Disable workflows

* Try fix

* Split check workflow in two jobs

* Try invalid license header

* Comment of failure

* Disable cppcheck job

* Fix licenserc file

* Enable debug logging

* Prevent comments from licence-eye

* Revert "Disable cppcheck job"

This reverts commit 10f55373ea.

* Revert "Disable workflows"

This reverts commit 2e2ead2fa5.

* Fix typo

* Revert "Try invalid license header"

This reverts commit 0cc0c883d2.

* Update year in license headers

* Cleanup

* Fix indention in license header

.licenserc.yaml

@@ -0,0 +1,19 @@
+header:
+  paths:
+    - "**/*.c"
+    - "**/*.h"
+  license:
+    pattern: |
+      .*\.(c|h)
+      .*
+
+      Portions Copyright © 2018-2024, Percona LLC and/or its affiliates
+
+      Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+
+      Portions Copyright (c) 1994, The Regents of the University of California
+
+      IDENTIFICATION
+         contrib/pg_stat_monitor/.*\.(c|h)
+
+  comment: never