*: git.monogon.dev -> source.monogon.dev

This implements T882, setting our (virtual) GOPATH to source.monogon.dev
for this repository.

Test Plan: Refactor, CI only.

X-Origin-Diff: phab/D686
GitOrigin-RevId: c5e2309089948ffc3a98e68e2e0e1cbb157d3a36
diff --git a/build/savestdout/BUILD.bazel b/build/savestdout/BUILD.bazel
index 7208c6d..f37c603 100644
--- a/build/savestdout/BUILD.bazel
+++ b/build/savestdout/BUILD.bazel
@@ -3,7 +3,7 @@
 go_library(
     name = "go_default_library",
     srcs = ["savestdout.go"],
-    importpath = "git.monogon.dev/source/nexantic.git/build/savestdout",
+    importpath = "source.monogon.dev/build/savestdout",
     visibility = ["//visibility:private"],
 )