Update build.yml

Author: Germey

.github/workflows/build.yml

@@ -28,7 +28,11 @@ jobs:
         with:
           username: germey
           password: ${{ secrets.DOCKERHUB_LOGIN_PASSWORD }}
-
+      
+      - name: Get current date
+        id: date
+        run: echo "::set-output name=date::$(date +'%Y%m%d')"
+      
       - name: Build and push
         uses: docker/build-push-action@v2
         with:
@@ -38,3 +42,4 @@ jobs:
           tags: |
             germey/proxypool:latest
             germey/proxypool:master
+            germey/proxypool:${{ steps.date.outputs.date }}