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/vmihailenco/msgpack/v5/.travis.yml

@@ -0,0 +1,20 @@
+sudo: false
+language: go
+
+go:
+  - 1.15.x
+  - 1.16.x
+  - tip
+
+matrix:
+  allow_failures:
+    - go: tip
+
+env:
+  - GO111MODULE=on
+
+go_import_path: github.com/vmihailenco/msgpack
+
+before_install:
+  - curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go
+    env GOPATH)/bin v1.31.0