add docker repo override to readme action

Author: NorskNoobing

.github/workflows/update-dockerhub-readme.yaml

@@ -10,11 +10,14 @@ jobs:
   update_readme:
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+        
       - name: Docker Hub Description
-        uses: peter-evans/dockerhub-description@v3
+        uses: peter-evans/dockerhub-description@v4
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
-          repository: ${{ github.repository }}
+          repository: ${{ secrets.DOCKER_REPO || github.repository }}
           readme-filepath: ./README.md
           short-description: ${{ github.event.repository.description }}