Improve CI with a demo app project creation + build

.ci/test_project.sh

@@ -0,0 +1,11 @@
+
+#!/bin/bash
+
+set -eo pipefail
+
+python3 toolchain.py create Touchtracer kivy-ci-clone/examples/demo/touchtracer
+
+xcodebuild -project touchtracer-ios/touchtracer.xcodeproj \
+            -scheme touchtracer \
+            -destination generic/platform=iOS\
+            clean build CODE_SIGNING_ALLOWED=NO | xcpretty

.github/workflows/kivy_ios.yml

@@ -35,9 +35,18 @@ jobs:
         brew install autoconf automake libtool pkg-config
         brew link libtool
         pip3 install Cython==0.28.1
+        gem install xcpretty
     - name: Build Python & Kivy
       run: |
         python toolchain.py build python3 kivy
+    - name: Checkout kivy for tests apps
+      uses: actions/checkout@v2
+      with:
+        repository: kivy/kivy
+        path: kivy-ci-clone
+    - name: Create & Build test project
+      run: |
+        .ci/test_project.sh
 
   build_updated_recipes:
     runs-on: macos-latest