Update README.md

[tvitcom]

Fix without v2 path

[tvitcom]

For new comers

[coveralls]

Coverage remained the same at 93.931% when pulling a0f7c17 on tvitcom:master into fc6e6ff on go-ozzo:master.

[qiangxue]

The v2 tag is correct. You do need to run go get under your project that uses go mod to manage dependencies. I've fixed the go-rest-api link. Thanks for your contribution!