*: 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/node/kubernetes/nfproxy/nfproxy.go b/metropolis/node/kubernetes/nfproxy/nfproxy.go
index cfdfda4..ac13af1 100644
--- a/metropolis/node/kubernetes/nfproxy/nfproxy.go
+++ b/metropolis/node/kubernetes/nfproxy/nfproxy.go
@@ -38,7 +38,7 @@
 	"k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/tools/record"
 
-	"git.monogon.dev/source/nexantic.git/metropolis/pkg/supervisor"
+	"source.monogon.dev/metropolis/pkg/supervisor"
 )
 
 type Service struct {