Merge pull request #7803 from emqx/ci/william/build-slim-self-hosted

ci: build slim packages on self-hosted runners

.github/workflows/build_slim_packages.yaml

@@ -23,7 +23,7 @@ on:
 
 jobs:
   linux:
-    runs-on: ubuntu-20.04
+    runs-on: aws-amd64
 
     strategy:
       fail-fast: false
@@ -43,6 +43,7 @@ jobs:
     container: "ghcr.io/emqx/emqx-builder/5.0-10:${{ matrix.elixir }}-${{ matrix.otp }}-${{ matrix.os }}"
 
     steps:
+    - uses: AutoModality/action-clean@v1
     - uses: actions/checkout@v1
     - name: prepare
       run: |