Run CI against Windows Store Python; Set up Dependabot

- Unset `WIX` env var so Briefcase installs WiX itself.
- Add `3.12-dev` to Python matrix.

.github/workflows/ci.yml

@@ -8,52 +8,60 @@ on:
 
 defaults:
   run:
-    shell: bash # https://github.com/beeware/briefcase/pull/912
+    shell: bash  # https://github.com/beeware/briefcase/pull/912
 
 jobs:
   verify-apps:
     name: Build apps
+    runs-on: windows-latest
+    continue-on-error: ${{ matrix.experimental }}
+    timeout-minutes: 20
     strategy:
       fail-fast: false
       matrix:
-        python_version: ["3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12-dev"]
+        python-source: ["github", "winstore"]
         framework: ["toga", "pyside2", "pyside6", "ppb"]
         include:
-          - platform: windows-latest
-            briefcase-data-dir: ~\AppData\Local\BeeWare\briefcase\Cache
-            pip-cache-dir: ~\AppData\Local\pip\Cache
-            docker-cache-dir: C:\ProgramData\DockerDesktop
-
+          - experimental: false
+          - python-version: "3.12-dev"
+            experimental: true
         exclude:
+          - python-version: "3.12-dev"
+            python-source: "winstore"
           # PySide2 doesn't publish a binary wheel that is compatible
           # with Python 3.11, and is unlikely to ever do so.
-          - python_version: "3.11"
+          - python-version: "3.11"
             framework: "pyside2"
-
-    runs-on: ${{ matrix.platform }}
     steps:
       - name: Cache Briefcase tools
         uses: actions/cache@v3.0.11
         with:
-          key: briefcase-${{ matrix.platform }}-${{ matrix.python_version }}
+          key: briefcase-${{ runner.os }}-${{ matrix.python-version }}
           path: |
             ~/.cookiecutters
-            ${{ matrix.briefcase-data-dir }}
-            ${{ matrix.pip-cache-dir }}
-            ${{ matrix.docker-cache-dir }}
+            ~/AppData/Local/BeeWare/briefcase/Cache
+            ~/AppData/Local/pip/Cache
       - uses: actions/checkout@v3.1.0
         with:
           fetch-depth: 0
       - name: Set up Python
+        if: matrix.python-source == 'github'
         uses: actions/setup-python@v4.3.0
         with:
-          python-version: ${{ matrix.python_version }}
+          python-version: ${{ matrix.python-version }}
+      - name: Install Windows Store Python
+        if: matrix.python-source == 'winstore'
+        uses: beeware/.github/.github/actions/install-win-store-python@main
+        with:
+          python-version: ${{ matrix.python-version }}
       - name: Install dependencies
         run: |
           python -m pip install briefcase
       - name: Build App
         run: |
+          unset WIX  # force Briefcase to install and use its own version of WiX
           cd tests/apps/verify-${{ matrix.framework }}
-          briefcase create
-          briefcase build
-          briefcase package --adhoc-sign
+          briefcase create -v
+          briefcase build -v
+          briefcase package --adhoc-sign -v

.github/workflows/dependabot-changenote.yml

@@ -0,0 +1,12 @@
+name: Dependabot Change Note
+
+on:
+  push:
+    branches:
+      - 'dependabot/**'
+
+jobs:
+  changenote:
+    name: Dependabot Change Note
+    uses: beeware/.github/.github/workflows/dependabot-changenote.yml@main
+    secrets: inherit

.gitignore

@@ -1,6 +1,7 @@
 .DS_Store
 .python-version
 .vscode
+.idea
 venv/
 stub/windows/
-stub/briefcase.*.log
+stub/briefcase.*.log