[workflows] add cff validation

Author: pdiercks

.github/workflows/cff.yml

@@ -0,0 +1,22 @@
+name: validate-citation-file
+
+on:
+  push:
+    paths:
+      - CITATION.cff
+  workflow_dispatch:
+
+name: CITATION.cff
+jobs:
+  Validate-CITATION-cff:
+    runs-on: ubuntu-latest
+    name: Validate CITATION.cff
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Validate CITATION.cff
+        uses: dieghernan/cff-validator@main