chore: prepare 6.3.1 release (#239)

Author: peknur

CHANGELOG.md

@@ -5,6 +5,8 @@ See updating [Changelog example here](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 
+## [6.3.1]
+
 ### Added
 - Managed Load Balancer inverse rule matcher
 
@@ -299,7 +301,8 @@ See updating [Changelog example here](https://keepachangelog.com/en/1.0.0/)
 
 First stable release
 
-[Unreleased]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.3.0...HEAD
+[Unreleased]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.3.1...HEAD
+[6.3.1]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.3.0...v6.3.1
 [6.3.0]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.2.0...v6.3.0
 [6.2.0]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.1.1...v6.2.0
 [6.1.1]: https://github.com/UpCloudLtd/upcloud-go-api/compare/v6.1.0...v6.1.1

upcloud/client/client.go

@@ -16,7 +16,7 @@ import (
 )
 
 const (
-	Version    string = "6.3.0"
+	Version    string = "6.3.1"
 	APIVersion string = "1.3"
 	APIBaseURL string = "https://api.upcloud.com"