v2.15.0

• Bump minimal Go version to 1.17
• Bump golang.org/x/net to 0.7.0
• Support colored output (#161, #335)
• Support thousand separation when formatting numbers (#274)
• Print HTTP request and response in failure message (#159)
• Add RequestFactoryFunc, ClientFunc, WebsocketDialerFunc, ReporterFunc, LoggerFunc (#249)
• Add PanicReporter (#248)
• Fix error messages in AssertReporter and RequireReporter (1e30c27)
• Update documentation
• Improve test coverage
• Refactor and cleanup tests