Fix case sensitivity in Docker image tags

Author: masecla22

.github/workflows/docker-image.yml

@@ -22,6 +22,6 @@ jobs:
         password: ${{ secrets.GITHUB_TOKEN }}
     - name: Build the Docker image
       run: |
-          docker build . --file Dockerfile --tag ghcr.io/Code-For-Groningen/Remindify:latest
-          docker push ghcr.io/Code-For-Groningen/Remindify:latest
+          docker build . --file Dockerfile --tag ghcr.io/code-for-groningen/remindify:latest
+          docker push ghcr.io/code-for-groningen/remindify:latest