Add size trends report step to CI workflow (#133)

On every push to the master branch, size data will be written to a Google Sheets spreadsheet.

This information will allow tracking the trends in memory usage over time.

Author: per1234

.github/workflows/compile-examples.yml

@@ -77,6 +77,14 @@ jobs:
           size-report-sketch: 'ArduinoIoTCloud_Travis_CI'
           enable-size-deltas-report: 'true'
 
+      - name: Write data to size trends report spreadsheet
+        # Update report on every push to the master branch
+        if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+        uses: arduino/actions/libraries/report-size-trends@master
+        with:
+          google-key-file: ${{ secrets.GOOGLE_KEY_FILE }}
+          spreadsheet-id: 1I6NZkpZpf8KugBkE92adB1Z3_b7ZepOpCdYTOigJpN4
+
       - name: Save memory usage change report as artifact
         if: github.event_name == 'pull_request'
         uses: actions/upload-artifact@v1