CONTRIBUTORS: add Paul Murphy (IBM corporate CLA)
CONTRIBUTORS: add Paul Murphy (IBM corporate CLA)

Change-Id: I9fecc76f8cbda364b467eab7b2e7381b963df892
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/255137
Trust: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Trust: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>
Reviewed-by: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

golang/gofrontend,golang/gofrontend,golang/gofrontend,golang/gofrontend