Update lucacome/docker-image-update-checker action to v3 (#4031)

| datasource  | package                              | from   | to     |
| ----------- | ------------------------------------ | ------ | ------ |
| github-tags | lucacome/docker-image-update-checker | v2.0.0 | v3.0.0 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/update-docker-images.yml

@@ -67,7 +67,7 @@ jobs:
 
       - name: Check if update available for nginx image
         id: update
-        uses: lucacome/docker-image-update-checker@a233de0585661c019fb71f9601328db37051cc66 # v2.0.0
+        uses: lucacome/docker-image-update-checker@5d84572804be8bd4dc353f08c8437efdb6af37ac # v3.0.0
         with:
           base-image: ${{ needs.variables.outputs.nginx_version }}
           image: ghcr.io/nginx/nginx-gateway-fabric/nginx:${{ needs.variables.outputs.ngf_tag }}