[Bug Fix] Rename devcontainer image to repo-owned package (#413)

The docker-build job has failed on every main run since the monorepo
unification (#358) with `denied: permission_denied: write_package` —
the ghcr.io/ruby-ui/web-devcontainer package belongs to the archived
ruby-ui/web repo, so this repo's GITHUB_TOKEN cannot push to it.

Renaming to ghcr.io/ruby-ui/ruby_ui-devcontainer lets the first push
create a fresh package linked to this repo with write access. The image
is only used as a CI build cache (devcontainer.json builds from the
local Dockerfile), so nothing consumes the old name.

Author: djalmaaraujo

.github/workflows/ci.yml

@@ -123,7 +123,7 @@ jobs:
       - name: Build and push devcontainer image
         uses: devcontainers/ci@v0.3
         with:
-          imageName: ghcr.io/ruby-ui/web-devcontainer
-          cacheFrom: ghcr.io/ruby-ui/web-devcontainer
+          imageName: ghcr.io/ruby-ui/ruby_ui-devcontainer
+          cacheFrom: ghcr.io/ruby-ui/ruby_ui-devcontainer
           subFolder: docs
           push: always