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/api-put-object-common.go

@@ -26,6 +26,8 @@ import (
 	"github.com/minio/minio-go/v7/pkg/s3utils"
 )
 
+const nullVersionID = "null"
+
 // Verify if reader is *minio.Object
 func isObject(reader io.Reader) (ok bool) {
 	_, ok = reader.(*Object)
@@ -130,7 +132,7 @@ func OptimalPartInfo(objectSize int64, configuredPartSize uint64) (totalPartsCou
 
 // getUploadID - fetch upload id if already present for an object name
 // or initiate a new request to fetch a new upload id.
-func (c Client) newUploadID(ctx context.Context, bucketName, objectName string, opts PutObjectOptions) (uploadID string, err error) {
+func (c *Client) newUploadID(ctx context.Context, bucketName, objectName string, opts PutObjectOptions) (uploadID string, err error) {
 	// Input validation.
 	if err := s3utils.CheckValidBucketName(bucketName); err != nil {
 		return "", err