Change from master to stable branch of deployment script

Author: dshanske

.github/workflows/deploy.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - 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 }}