Merge pull request #120 from rexagod/restore-contributingmd-ksm

Restore upstream CONTRIBUTING.md for `kube-state-metrics`

Author: simonpasquier

.github/workflows/merge-kube-state-metrics.yaml

@@ -24,6 +24,7 @@ jobs:
         .github/ 
         .markdownlint-cli2.jsonc
         CHANGELOG.md
+        CONTRIBUTING.md
         Dockerfile
         RELEASE.md
         VERSION