add format-dart to makefile

Makefile

@@ -2,15 +2,18 @@
 
 OBJC_SOURCES := $(shell find . \( -path './example/ios/Runner*' -o -path './ios/Classes/*' \) -a \( -name '*.h' -o -name '*.m' \))
 JAVA_SOURCES := $(shell find . -name '*.java')
+DART_SOURCES := $(shell find . -name '*.dart')
 
 help:
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 
-format: format-java format-objective-c ## Formats all java and objective-c files
+format: format-java format-objective-c format-dart ## Formats all java, objective-c and dart files
 
 format-java: $(JAVA_SOURCES) ## Format Java files (*.java)
 	google-java-format --replace $^
 
 format-objective-c: $(OBJC_SOURCES) ## Format Objective-C header and implementation files (*.h, *.m)
 	clang-format -i --style=Google $^
 
+format-dart: $(DART_SOURCES) ## Format Dart files (*.dart)
+	flutter format $^