gha/bin-image: add major and minor version image tags

Adding image tags that follow the semver major and minor versions (e.g., `28`
and `28.3`) for the moby-bin images.

This makes it easier for users to reference the latest build within a
major or minor version series without having to know the exact
minor/patch version.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

.github/workflows/build.yml

@@ -121,6 +121,8 @@ jobs:
             type=semver,pattern={{version}}
             type=ref,event=branch
             type=ref,event=pr
+            type=semver,pattern={{major}}
+            type=semver,pattern={{major}}.{{minor}}
       -
         name: Build and push image
         uses: docker/bake-action@v6