*: 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/metropolis/test/launch/launch.go b/metropolis/test/launch/launch.go
index 21d066b..6e6891a 100644
--- a/metropolis/test/launch/launch.go
+++ b/metropolis/test/launch/launch.go
@@ -39,9 +39,9 @@
 	"golang.org/x/sys/unix"
 	"google.golang.org/grpc"
 
-	"git.monogon.dev/source/nexantic.git/metropolis/node"
-	"git.monogon.dev/source/nexantic.git/metropolis/pkg/freeport"
-	apb "git.monogon.dev/source/nexantic.git/metropolis/proto/api"
+	"source.monogon.dev/metropolis/node"
+	"source.monogon.dev/metropolis/pkg/freeport"
+	apb "source.monogon.dev/metropolis/proto/api"
 )
 
 type qemuValue map[string][]string