add license headers check to sanity script (#106)
add license headers check to sanity script (#106)

Motivation:

prevent adding source that does not include the license header

Modifications:

add a check in sanity script to grep over all swift files and make sure they have the license header

Result:

ci build will fail if/when trying to commit source files that do not include the license header
apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio