Re-add version tag

Signed-off-by: Tommy <contact@tommytran.io>

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/build.yml

@@ -29,6 +29,11 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Extract version for tags
+        run: |
+          echo "FULL_VERSION=$(grep -oP '(?<=SYNAPSE_VERSION=).*' Dockerfile)" >> $GITHUB_ENV
+          echo "MAJOR_VERSION=$(grep -oP '(?<=SYNAPSE_VERSION=).*' Dockerfile | head -c5)" >> $GITHUB_ENV
+
       - name: Install cosign
         if: github.event_name != 'pull_request'
         uses: sigstore/cosign-installer@v3
@@ -51,6 +56,8 @@ jobs:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           tags: |
             latest
+            ${{ env.FULL_VERSION }}
+            ${{ env.MAJOR_VERSION }}
 
       - name: Build and push Docker image
         id: build-and-push