Update the lint version requirements in README.md
Update the lint version requirements in README.md

Per the discussion in #400, lint is supported under the same policy as Go itself, and is not supported from a particular version any more.

Change-Id: I97c9b284fb725b19143462ae22c525b22267257d
GitHub-Last-Rev: 73cd8baafc34121a88c420628e24900221a170d7
GitHub-Pull-Request: golang/lint#401
Reviewed-on: https://go-review.googlesource.com/110115
Reviewed-by: Andrew Bonventre <682ad9f487f614f19e8b7cc5d340bdc8e1c1b128@golang.org>

golang/lint