ci: add workflow for legacy branch release (#455)

Author: arjunsridhar12345

.github/workflows/publish_legacy.yml

@@ -0,0 +1,33 @@
+name: Publish legacy[v0] docker image
+on:
+  push:
+    branches:
+      - "legacy"
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Compute new docker image tag
+        run: |
+          echo "sha_short=$(git rev-parse --short "$GITHUB_SHA")" >> "$GITHUB_ENV"
+          echo "branch=$(echo ${GITHUB_REF_NAME})" >> "$GITHUB_ENV"
+          echo "docker_tag=$(echo legacy)-$(git rev-parse --short "$GITHUB_SHA")" >> "$GITHUB_ENV"
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Login to Github Packages
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build image and push to GitHub Container Registry
+        uses: docker/build-push-action@v3
+        with:
+          # relative path to the place where source code with Dockerfile is located
+          context: .
+          push: true
+          tags: |
+            ghcr.io/allenneuraldynamics/aind-metadata-mapper:${{ env.docker_tag }}