fix: fix dns on linux (#336)

* fix: fix dns on linux

* feat: detect run in Github action or not to setup DNS

vendor/github.com/tailscale/netlink/fou_unspecified.go

@@ -0,0 +1,15 @@
+// +build !linux
+
+package netlink
+
+func FouAdd(f Fou) error {
+	return ErrNotImplemented
+}
+
+func FouDel(f Fou) error {
+	return ErrNotImplemented
+}
+
+func FouList(fam int) ([]Fou, error) {
+	return nil, ErrNotImplemented
+}