Pass DOCKER_TOKEN secret into Docker workflow

Author: neilalexander

.github/workflows/dendrite.yml

@@ -342,3 +342,5 @@ jobs:
     if: github.repository == 'matrix-org/dendrite' && github.ref_name == 'main'
     needs: [integration-tests-done]
     uses: matrix-org/dendrite/.github/workflows/docker.yml@main
+    secrets:
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}

.github/workflows/docker.yml

@@ -7,6 +7,9 @@ on:
     types: [published]
   workflow_dispatch: # A build was manually requested
   workflow_call: # Another pipeline called us
+    secrets:
+      DOCKER_TOKEN:
+        required: true
 
 env:
   DOCKER_NAMESPACE: matrixdotorg