Update docker image tags (#27)

Builds triggered by push to main now use
 * "dev" instead of "latest"
 * the short commit "sha"
to better distinguish dev builds and release builds.

Builds triggered by bush of a v* tag still use "latest" by default,
see https://github.com/docker/metadata-action?tab=readme-ov-file#latest-tag

Signed-off-by: Lukas Puehringer <lukas.puehringer@eclipse-foundation.org>

Author: lukpueh

.github/workflows/publish.yml

@@ -42,7 +42,8 @@ jobs:
           type=semver,pattern={{version}}
           type=semver,pattern={{major}}.{{minor}}
           type=semver,pattern={{major}}
-          type=raw,value=latest,enable={{is_default_branch}}
+          type=raw,value=dev,enable={{is_default_branch}}
+          type=sha,enable={{is_default_branch}}
 
     - name: Build and push Docker image
       uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83