Create CITATION check action (#5)

* Create CITATION check action

* Fix formatting and run on pushes to main

.github/workflows/citation-check.yml

@@ -0,0 +1,21 @@
+on:
+  workflow_dispatch:
+  push:
+    branches: main
+    paths:
+    - CITATION.cff
+
+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@v4
+
+      - name: Validate CITATION.cff
+        uses: dieghernan/cff-validator@v3