ci: update linter to run on pull requests to main and staging (#456)

The required linters are not running on pull requests from forked repositories. This fix is intended to trigger the linters on any pull request going to the main or staging branch.

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Signed-off-by: chjmil <[email protected]>

Author: saschjmil

.github/workflows/linter-analysis.yaml

@@ -1,7 +1,9 @@
 name: Linter Analysis
 on:
-  push:
-    branches: ['**'] # '*' will cause the workflow to run on all commits to all branches.
+  pull_request:
+    branches:
+    - main
+    - staging
 
 jobs:
   # Hadolint: Job-1