fix github workflow

Author: yingziwu

.github/workflows/docker.yml

@@ -27,16 +27,15 @@ jobs:
         uses: docker/login-action@v2
         with:
           registry: ghcr.io
-          username: ${{ github.repository_owner }}
+          username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Calculate docker image tag
         id: set-tag
         uses: docker/metadata-action@master
         with:
           images: |
-            docker.io/matrixdotorg/synapse
-            ghcr.io/matrix-org/synapse
+            ghcr.io/yingziwu/synapse
           flavor: |
             latest=false
           tags: |