Don't push/login to docker in forks.

.github/workflows/build.yml

@@ -24,6 +24,7 @@ jobs:
     env:
       DOCKER_REPO: sippylabs/webrtc_phone
       BASE_IMAGE: sippylabs/rtpproxy:RFC5245_ICE-ubuntu_latest
+      DOCKER_RW: ${{ ( github.repository == 'sippy/webrtc_phone' && github.event_name != 'pull_request' ) && 'true' || 'false' }}
     steps:
     - name: Checkout repository
       uses: actions/checkout@v4
@@ -64,7 +65,7 @@ jobs:
       uses: docker/setup-buildx-action@v3
 
     - name: Log in to Docker Hub
-      if: github.event_name != 'pull_request'
+      if: ${{ env.DOCKER_RW }}
       uses: docker/login-action@v3
       with:
         username: ${{ secrets.DOCKER_USERNAME }}
@@ -97,7 +98,7 @@ jobs:
         context: .
         file: ./Dockerfile
         build-args: BASE_IMAGE=${{ env.BASE_IMAGE }}
-        push: true
+        push: ${{ env.DOCKER_RW }}
         tags: |
           ${{ steps.meta.outputs.tags }}
         labels: ${{ steps.meta.outputs.labels }}
@@ -106,7 +107,7 @@ jobs:
         cache-to: ${{ env.CACHE_SPEC }},mode=max
 
     - name: Update DockerHub repo description
-      if: ${{ github.ref == format('refs/heads/{0}', github.event.repository.default_branch) }}
+      if: ${{ env.DOCKER_RW }} && ${{ github.ref == format('refs/heads/{0}', github.event.repository.default_branch) }}
       env:
         DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
         DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}