README.md,CONTRIBUTING.md: rename go.dev label to pkgsite

The go.dev label will be renamed to pkgsite, since all of the
issues we have been receiving and using that label for have
been related to x/pkgsite.

Change-Id: I1f1aabe42ea537aa45bc5fae84868a2f33aba9c5
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/242537
Reviewed-by: Andrew Bonventre <andybons@golang.org>

CONTRIBUTING.md

@@ -16,10 +16,10 @@ any contributions for
 ## Finding issues
 
 All issues related to x/pkgsite are labeled with the
-[`go.dev` label](https://github.com/golang/go/issues/labels/go.dev).
+[`pkgsite` label](https://github.com/golang/go/issues/labels/pkgsite).
 
 In particular, we would love your help on issues tagged with the
-[`help wanted` label](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Ago.dev+label%3A%22help+wanted%22+).
+[`help wanted` label](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Apkgsite+label%3A%22help+wanted%22+).
 
 Before you begin working on an issue, please leave a comment that you are claiming it.
 

README.md

@@ -15,7 +15,7 @@ Here's what we are currently working on:
 
 - Design updates: We have some design changes planned for pkg.go.dev,
   to address
-  [UX feedback](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Ago.dev+label%3AUX)
+  [UX feedback](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Apkgsite+label%3AUX)
   that we have received.
   You can expect a more cohesive search and navigation experience coming soon.
   We plan to share these designs for feedback once they are ready.
@@ -47,7 +47,7 @@ the [known issues](https://github.com/golang/go/labels/go.dev) to see if your
 issue is already being discussed. If an issue does not already exist, feel free
 to [file an issue](https://golang.org/s/discovery-feedback).
 
-For answers to frequently asked questions, see [go.dev](https://go.dev/about).
+For answers to frequently asked questions, see [go.dev/about](https://go.dev/about).
 
 You can also chat with us on the #tools slack channel on the
 [Gophers slack](https://invite.slack.golangbridge.org).