Bump home-assistant/builder from 2021.07.0 to 2021.09.0 (#86)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/builder.yml

@@ -73,7 +73,7 @@ jobs:
       run: echo "BUILD_ARGS=--test" >> $GITHUB_ENV
 
     - name: Build plugin
-      uses: home-assistant/builder@2021.07.0
+      uses: home-assistant/builder@2021.09.0
       with:
         args: |
           $BUILD_ARGS \