README: don't mention GOPATH

Add a pointer to the git repo.

For golang/go#62645

Change-Id: Ie28be88c7ed4ff3f0f758a7cf8f1c5bf64e5a1f3
Reviewed-on: https://go-review.googlesource.com/c/review/+/624215
Commit-Queue: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
diff --git a/README.md b/README.md
index c17c0fa..1f92655 100644
--- a/README.md
+++ b/README.md
@@ -4,16 +4,17 @@
 
 ## Download/Install
 
-The easiest way to install is to run `go install golang.org/x/review/git-codereview@latest`. You can
-also manually git clone the repository to `$GOPATH/src/golang.org/x/review`.
+The easiest way to install is to run `go install golang.org/x/review/git-codereview@latest`.
 
 Run `git codereview hooks` to install Gerrit hooks for your git repository.
 
 ## Report Issues / Send Patches
 
 This repository uses Gerrit for code changes. To learn how to submit changes to
-this repository, see https://golang.org/doc/contribute.html.
+this repository, see https://go.dev/doc/contribute.
+
+The git repository is https://go.googlesource.com/review.
 
 The main issue tracker for the review repository is located at
-https://github.com/golang/go/issues. Prefix your issue with "x/review:" in the
+https://go.dev/issues. Prefix your issue with "x/review:" in the
 subject line, so it is easy to find.