Remove maintainers.md use only contributing.md (#8215)

MAINTAINERS.md

@@ -1,37 +0,0 @@
-# For maintainers only
-
-### Setup your minio GitHub Repository
-
-Fork [minio upstream](https://github.com/minio/minio/fork) source repository to your own personal repository.
-```bash
-$ mkdir -p $GOPATH/src/github.com/minio
-$ cd $GOPATH/src/github.com/minio
-$ git clone https://github.com/$USER_ID/minio
-$ 
-```
-
-``minio`` uses [govendor](https://github.com/kardianos/govendor) for its dependency management.
-
-### To manage dependencies
-
-#### Add new dependencies
-
-  - Run `go get foo/bar`
-  - Edit your code to import foo/bar
-  - Run `govendor add foo/bar` from top-level directory
-
-#### Remove dependencies 
-
-  - Run `govendor remove foo/bar`
-
-#### Update dependencies
-
-  - Run `govendor remove +vendor`
-  - Run to update the dependent package `go get -u foo/bar`
-  - Run `govendor add +external`
-
-### Making new releases 
-
-`minio` doesn't follow semantic versioning style, `minio` instead uses the release date and time as the release versions.
-
-`make release` will generate new binary into `release` directory.