Flank v4.0.0

Release for commit 7eea0f7

• Add flank cancel command. See flank cancel --help
• Add flank refresh command. See flank refresh --help
• Automatically detect projectId from service account credential
• Always generate aggregated JUnit XML reports
• Update HTML report to use create-react-app v2.1.0
• Add support for Xcode 10.1
• Improve test parsing to detect Swift tests that throw errors
• Update Flank exit codes, see readme for details.
• Link to matrix root when testing on multiple devices