Bump github.com/mattermost/mattermost-server/v6 from 6.1.0 to 6.3.0 (#1686)

Bumps [github.com/mattermost/mattermost-server/v6](https://github.com/mattermost/mattermost-server) from 6.1.0 to 6.3.0.
- [Release notes](https://github.com/mattermost/mattermost-server/releases)
- [Changelog](https://github.com/mattermost/mattermost-server/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mattermost/mattermost-server/compare/v6.1.0...v6.3.0)

---
updated-dependencies:
- dependency-name: github.com/mattermost/mattermost-server/v6
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

vendor/github.com/minio/minio-go/v7/pkg/signer/utils.go

@@ -44,6 +44,10 @@ func sumHMAC(key []byte, data []byte) []byte {
 
 // getHostAddr returns host header if available, otherwise returns host from URL
 func getHostAddr(req *http.Request) string {
+	host := req.Header.Get("host")
+	if host != "" && req.Host != host {
+		return host
+	}
 	if req.Host != "" {
 		return req.Host
 	}