CONTRIBUTORS: add Paul Murphy (IBM corporate CLA)

Change-Id: I9fecc76f8cbda364b467eab7b2e7381b963df892
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/255137
Trust: Ian Lance Taylor <iant@golang.org>
Trust: Than McIntosh <thanm@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
1 file changed