fix github action branch

Author: pfefferle

.github/workflows/deploy.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
     - uses: actions/checkout@master
     - name: WordPress Plugin Deploy
-      uses: 10up/action-wordpress-plugin-deploy@master
+      uses: 10up/action-wordpress-plugin-deploy@stable
       env:
         SVN_PASSWORD: ${{ secrets.SVN_PASSWORD }}
         SVN_USERNAME: ${{ secrets.SVN_USERNAME }}