ci: audit workflows with zizmor

.github/workflows/publish-deltachat-rpc-client-pypi.yml

@@ -5,6 +5,8 @@ on:
   release:
     types: [published]
 
+permissions: {}
+
 jobs:
   build:
     name: Build distribution
@@ -14,6 +16,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           show-progress: false
+          persist-credentials: false
       - name: Install pypa/build
         run: python3 -m pip install build
       - name: Build a binary wheel and a source tarball