Add new workflow to test dart-dio samples #8

Job	Run time
test (windows-latest, 3.7.0, samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-j...	24s
test (ubuntu-latest, 3.7.0, samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-js...	21s
	45s

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