SwiftLint script file

[AvdLee]

Add this to a script file:

if [ -z "$CI" ]; then
    if which swiftlint >/dev/null; then
        swiftlint --config "${SRCROOT}/Submodules/WeTransfer-iOS-CI/SwiftLint/.swiftlint-source.yml"
        swiftlint --config "${SRCROOT}/Submodules/WeTransfer-iOS-CI/SwiftLint/.swiftlint-tests.yml"
    else
        echo "warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint"
    fi
fi

So it's easier to add and maintain. Also, let the project fail if SwiftLint is not installed