Fixing github workflow

Author: aentinger

.github/workflows/compile-examples.yml

@@ -71,7 +71,7 @@ jobs:
       - name: Compile examples
         uses: arduino/actions/libraries/compile-examples@master
         with:
-          platforms |
+          platforms: |
             - source-url: https://github.com/arduino/ArduinoCore-samd/archive/master.zip
           fqbn: ${{ matrix.board.fqbn }}
           libraries: "${{ env.UNIVERSAL_LIBRARIES }} ${{ matrix.libraries }}"