chore(deps): bump github.com/gin-gonic/gin from 1.4.0 to 1.9.1 (#38)

Bumps [github.com/gin-gonic/gin](https://github.com/gin-gonic/gin) from 1.4.0 to 1.9.1.
- [Release notes](https://github.com/gin-gonic/gin/releases)
- [Changelog](https://github.com/gin-gonic/gin/blob/master/CHANGELOG.md)
- [Commits](gin-gonic/gin@v1.4.0...v1.9.1)

---
updated-dependencies:
- dependency-name: github.com/gin-gonic/gin
  dependency-type: direct:production
...

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

go.mod

@@ -29,7 +29,7 @@ require (
  github.com/fsnotify/fsnotify v1.4.9
  github.com/getsentry/raven-go v0.2.0
  github.com/gin-gonic/contrib v0.0.0-20190526021735-7fb7810ed2a0
- github.com/gin-gonic/gin v1.4.0
+ github.com/gin-gonic/gin v1.9.1
  github.com/go-redis/redis/v8 v8.4.4
  github.com/go-sourcemap/sourcemap v2.1.2+incompatible // indirect
  github.com/gorilla/websocket v1.4.0 // indirect
@@ -66,6 +66,7 @@ require (
  golang.org/x/text v0.14.0
  google.golang.org/appengine v1.5.0 // indirect
  gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect
+ gopkg.in/go-playground/assert.v1 v1.2.1 // indirect
  gopkg.in/go-playground/validator.v8 v8.18.2
  gopkg.in/gomail.v2 v2.0.0-20160411212932-81ebce5c23df
  gopkg.in/mgo.v2 v2.0.0-20180705113604-9856a29383ce