Add "smoke test" examples compilation CI workflow

On every push or pull request that affects library source or example files, and periodically, compile all example
sketches for the specified boards.

.github/workflows/compile-examples.yml

@@ -0,0 +1,94 @@
+name: Compile Examples
+
+# See: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows
+on:
+  push:
+    paths:
+      - ".github/workflows/compile-examples.yml"
+      - "examples/**"
+      - "src/**"
+  pull_request:
+    paths:
+      - ".github/workflows/compile-examples.yml"
+      - "examples/**"
+      - "src/**"
+  schedule:
+    # Run every Tuesday at 8 AM UTC to catch breakage caused by changes to external resources (libraries, platforms).
+    - cron: "0 8 * * TUE"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  build:
+    name: ${{ matrix.board.fqbn }}
+    runs-on: ubuntu-latest
+
+      fail-fast: false
+
+      matrix:
+        board:
+          - fqbn: arduino:samd:arduino_zero_edbg
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkr1000
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrzero
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrwifi1010
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrfox1200
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrwan1300
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrwan1310
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrgsm1400
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrnb1500
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:mkrvidor4000
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:nano_33_iot
+            platforms: |
+              - name: arduino:samd
+          - fqbn: arduino:samd:tian
+            platforms: |
+              - name: arduino:samd
+            sketch-paths: |
+              - examples/TianStandby
+          - fqbn: arduino:nrf52:primo
+            platforms: |
+              - name: arduino:nrf52
+            sketch-paths: |
+              - examples/PrimoDeepSleep
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Compile examples
+        uses: arduino/compile-sketches@v1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          fqbn: ${{ matrix.board.fqbn }}
+          platforms: ${{ matrix.board.platforms }}
+          libraries: |
+            # Install the library from the local path.
+            - source-path: ./
+            - name: RTCZero
+          sketch-paths: |
+            # Sketches to compile for all boards
+            - examples/AdcWakeup
+            - examples/ExternalWakeup
+            - examples/TimedWakeup
+            # Board-specific sketches
+            ${{ matrix.board.sketch-paths }}

README.md

@@ -1,6 +1,7 @@
 # Arduino Low Power library
 
 [![Check Arduino status](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/check-arduino.yml/badge.svg)](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/check-arduino.yml)
+[![Compile Examples status](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/compile-examples.yml/badge.svg)](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/compile-examples.yml)
 [![Spell Check status](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/spell-check.yml/badge.svg)](https://github.com/arduino-libraries/ArduinoLowPower/actions/workflows/spell-check.yml)
 
 This library allows the use of the low power features of the SAMD21 MCU. This means your battery powered projects will have a longer battery life on boards like [MKRZero](https://store.arduino.cc/usa/arduino-mkrzero), [MKR1000](https://www.arduino.cc/en/Main/ArduinoMKR1000) and [MKRFox1200](https://www.arduino.cc/en/Main/ArduinoBoardMKRFox1200).