Auto pr (#106)

* auto update downstream repos on pushes

* fix github actions

* add workflow dispatch and token

.github/workflows/auto-pr.yml

@@ -0,0 +1,37 @@
+name: Downstream Updates
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        repo: [
+          raspberrypi-rp2040,
+        ]
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+      with:
+        repository: https://github.com/ZigEmbeddedGroup/${{ matrix.repo }}.git
+        submodules: recursive
+        fetch-depth: 0
+
+    - name: Update
+      run: |
+        cd deps/microzig
+        git pull origin main
+
+    - name: Create Pull Request
+      uses: peter-evans/create-pull-request@v4.2.3
+      with:
+        token: ${{ secrets.PR_TOKEN }}
+        branch: update-microzig
+        commit-message: update microzig
+        delete-branch: true
+        title: Update microzig
+