A+C: delete AUTHORS and CONTRIBUTORS

In 2009, Google's open-source lawyers asked us to create the AUTHORS
file to define "The Go Authors", and the CONTRIBUTORS file was in
keeping with open source best practices of the time.

Re-reviewing our repos now in 2022, the open-source lawyers are
comfortable with source control history taking the place of the
AUTHORS file, and most open source projects no longer maintain
CONTRIBUTORS files.

To ease maintenance, remove AUTHORS and CONTRIBUTORS from all repos.

For #53961.

Change-Id: I6f3becd863672356de571303ff31434f517d959e
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/418902
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Chase <drchase@google.com>
diff --git a/AUTHORS b/AUTHORS
deleted file mode 100644
index 2b00ddb..0000000
--- a/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at https://tip.golang.org/AUTHORS.
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
deleted file mode 100644
index 1fbd3e9..0000000
--- a/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at https://tip.golang.org/CONTRIBUTORS.