ci: update gcr push token

Signed-off-by: Nianyu Shen <xiaoyu9964@gmail.com>

.github/workflows/provider-packaging.yaml

@@ -40,5 +40,5 @@ jobs:
  - uses: earthly/actions-setup@v1
  with:
  version: "latest"
- - run: echo "${{ secrets.GCR_JSON_KEY_B64 }}" | base64 -d | docker login -u _json_key --password-stdin https://gcr.io
+ - run: echo "${{ secrets.GCR_DEV_PUBLIC_B64_TOKEN }}" | base64 -d | docker login -u _json_key --password-stdin https://gcr.io
  - run: earthly --ci --push +provider-package-all-platforms --IMAGE_REPOSITORY=gcr.io/spectro-dev-public/kairos-io