Add script for automatic push to standalone branch

.github/workflows/update_standalone.yml

@@ -0,0 +1,33 @@
+on:
+  push:
+    branches: [develop]
+
+name: Update standalone branch
+
+env:
+  STANDALONE_BRANCH_NAME: standalone
+
+jobs:
+  update:
+    name: Update standalone branch
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup git
+        run: |
+            git config --global user.email "$GITHUB_ACTOR@users.noreply.github.com"
+            git config --global user.name "$GITHUB_ACTOR"
+            git fetch
+      - name: Create standalone version
+        run: |
+          bash tools/create_standalone.sh /tmp/nowide_standalone
+          git checkout "$STANDALONE_BRANCH_NAME" -- || git checkout -b "$STANDALONE_BRANCH_NAME"
+          git rm -r *
+          mv /tmp/nowide_standalone/* .
+          git add .
+      - name: Commit and push
+        run: |
+          git commit -am "Include '${{github.event.head_commit.message}}'"
+          remote_repo="https://${GITHUB_ACTOR}:${{secrets.GITHUB_TOKEN}}@github.com/${GITHUB_REPOSITORY}.git"
+          git push "$remote_repo" HEAD:$STANDALONE_BRANCH_NAME
+