add changes workflow (#1913)

Author: dvora-h

.github/workflows/update-changes.yaml

@@ -0,0 +1,24 @@
+name: Update CHANGES File
+on:
+  push:
+    paths-ignore:
+      - 'CHANGES'
+    branches:
+      - master
+jobs:
+  update-changes:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+        with:
+          persist-credentials: false
+          fetch-depth: 0
+      - name: Update CHANGES file
+        run: |
+          sed -i '1s/^/* ${{ github.event.head_commit.message }}. Thanks @${{ github.actor }}\n/' changes
+      - name: Commit & Push changes
+        uses: actions-js/push@master
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          branch: master
+          message: ${{ github.event.head_commit.message }}