Fix YAML errors because I am smart

add missing env.
Somehow, I forgot to write `run` in `docker run`
tag -> tags

.github/workflows/cross-compiling-docker.yml

@@ -20,16 +20,15 @@ jobs:
         context: .
         file: ./.github/workflows/Dockerfile.builder
         load: true # load into local image store
-        tag: dendrite-builder:${{ matrix.target }}
+        tags: "dendrite-builder:${{ matrix.target }}"
     - name: copy built files out of docker
-       run: docker -v "$(pwd)/bin:/build/bin-out" builder:${{ matrix.target }} "/bin/sh" "-c" "cp -a /build/bin/* /build/bin-out"
+      run: docker run -v "$(pwd)/bin:/build/bin-out" builder:${{ matrix.target }} "/bin/sh" "-c" "cp -a /build/bin/* /build/bin-out"
     - uses: actions/upload-artifact@v2
       with:
         name: bin-${{ matrix.target }}
         path: ./bin
   build-monolith:
     needs: [compile]
-    local-registry:
     runs-on: ubuntu-latest
     services:
       registry:
@@ -41,7 +40,6 @@ jobs:
         target: [amd64, arm64, arm]
     env:
       DOCKER_HUB_USER: dendritegithub
-    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
     - uses: actions/download-artifact@v2
@@ -57,6 +55,6 @@ jobs:
       with:
         context: .
         file: ./.github/workflows/Dockerfile.copyin
-        platforms: ${{ DOCKER_TARGET }}
+        platforms: ${{ env.DOCKER_TARGET }}
         push: true
         tags: localhost:5000/matrixdotorg/dendrite-monolith:latest