Update docker-image.yml

We need to update the secrets used. That old token seems to have expired, and there is no reason to have that as a secret when actions will handle any github auth for us.

.github/workflows/docker-image.yml

@@ -19,7 +19,7 @@ jobs:
         with:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
-          password: ${{ secrets.CR_PAT }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push image
         uses: docker/build-push-action@v2