Add Edge Control board to CI workflow

Because none of the examples of the platform bundled libraries are really suitable for this board, I added some
compilations of representative built-in example sketches to provide a basic smoke test for the board.

Author: per1234

.github/workflows/compile-examples.yml

@@ -25,7 +25,10 @@ jobs:
     env:
       # sketch paths to compile (recursive) compatible with all boards
       UNIVERSAL_SKETCH_PATHS: |
-        - libraries/Scheduler
+        - extras/arduino-examples/examples/01.Basics/Fade
+        - extras/arduino-examples/examples/02.Digital/DigitalInputPullup
+        - extras/arduino-examples/examples/03.Analog/AnalogInput
+        - extras/arduino-examples/examples/04.Communication/MultiSerial
 
     strategy:
       fail-fast: false
@@ -35,13 +38,19 @@ jobs:
           - fqbn: arduino:mbed:nano33ble
           - fqbn: arduino:mbed:envie_m4
           - fqbn: arduino:mbed:envie_m7
+          - fqbn: arduino:mbed:edge_control
 
         # compile only the examples compatible with each board
         include:
           - board:
               fqbn: arduino:mbed:nano33ble
             additional-sketch-paths: |
               - libraries/PDM
+              - libraries/Scheduler
+              - libraries/ThreadDebug
+          - board:
+              fqbn: arduino:mbed:edge_control
+            additional-sketch-paths: |
               - libraries/ThreadDebug
           - board:
               fqbn: arduino:mbed:envie_m4
@@ -50,6 +59,7 @@ jobs:
               - libraries/KernelDebug
               - libraries/Portenta_SDCARD
               - libraries/Portenta_Video
+              - libraries/Scheduler
           - board:
               fqbn: arduino:mbed:envie_m7
             additional-sketch-paths: |
@@ -58,6 +68,7 @@ jobs:
               - libraries/Portenta_SDCARD
               - libraries/Portenta_System
               - libraries/Portenta_Video
+              - libraries/Scheduler
               - libraries/ThreadDebug
               - libraries/USBHOST
               - libraries/WiFi
@@ -76,6 +87,12 @@ jobs:
       - name: Install ArduinoCore-API
         run: mv "$GITHUB_WORKSPACE/ArduinoCore-API/api" "$GITHUB_WORKSPACE/cores/arduino"   
 
+      - name: Checkout built-in examples
+        uses: actions/checkout@v2
+        with:
+          repository: arduino/arduino-examples
+          path: extras/arduino-examples
+
       - name: Compile examples
         uses: arduino/actions/libraries/compile-examples@master
         with: