GitHub Action playwright patch (#232)

Adding GitHub action for playwright patching (fixes #230), which checks
 - The build.sh script dry run is working
 - Playwright patches can be applied
 - The configure step succeeds
This will hopefully catch any build configuration problems during merges.

.github/workflows/playwright.yml

@@ -0,0 +1,57 @@
+# This is a basic workflow to help you get started with Actions
+
+name: Playwright
+
+# Controls when the workflow will run
+on:
+  # Triggers the workflow on push or pull request events but only for the main branch
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+
+  # Test applying playwright patches and installing dependencies
+  patch:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Install Dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y   \
+               curl                 \
+               python3              \
+               python3-pip          \
+               python3.10-venv      \
+               tar                  \
+               zip                  \
+               unzip                \
+               git
+          python3 -m pip install setuptools
+
+      - name: Checkout release branch
+        uses: actions/checkout@v3
+        with:
+          ref: main
+          path: foxhound
+
+      - name: Dry Run
+        run: |
+          cd foxhound
+          cp taintfox_mozconfig_ubuntu .mozconfig
+          bash build.sh -p -n   
+    
+      - name: Patch
+        run: |
+          cd foxhound
+          bash build.sh -p -u -v
+
+      - name: Configure
+        run: |
+          cd foxhound
+          ./mach configure