[README] Remove stale instruction

go.mod was added in 2018 in http://fxrev.dev/201484, so the instruction
in invalid since then.

Intentionally self-reviewing this change to test something.

No code change.

Change-Id: I2daff067db7380777daf57ca8ad714caff4538ab
Reviewed-on: https://fuchsia-review.googlesource.com/c/infra/infra/+/472039
Reviewed-by: Marc-Antoine Ruel <maruel@google.com>
Commit-Queue: Marc-Antoine Ruel <maruel@google.com>
diff --git a/README.md b/README.md
index 5cafb55..cef0dd1 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,3 @@
 
 This repo contains tools and config files necessary to run infrastructure
 related to builds, code review, version control, and continuous integrations.
-
-In order to build the Go code, you must clone this repo into an appropriately
-named directory. This should do the trick:
-```sh
-REPO=fuchsia.googlesource.com/infra/infra
-git clone https://${REPO} $(go env GOPATH)/src/${REPO}
-```
-