Upgrade nanopb to prevent it using system protobuf #476

Job	Run time
ctest (Release)	8m 4s
build-plugins (shrapnel, Release)	5m 48s
build-firmware	2m 41s
ctest (Debug)	6m 24s
build-plugins (shrapnel, Debug)	4m 54s
ctest-sanitize (Release)	16m 14s
ctest-sanitize (Debug)	8m 40s
flutter-analyze	1m 59s
flutter-format	1m 30s
flutter-test	2m 22s
license-headers	47s
coveralls-finish	4s
	59m 27s

Provide feedback