Fix generated protos and update go.mod to 1.18

go.mod

@@ -1,22 +1,27 @@
 module github.com/openconfig/gnmi
 
-go 1.12
+go 1.18
 
 require (
-	github.com/cenkalti/backoff/v4 v4.1.0
+	github.com/cenkalti/backoff/v4 v4.1.1
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
-	github.com/golang/protobuf v1.4.3
 	github.com/google/go-cmp v0.5.7
 	github.com/kylelemons/godebug v1.1.0
-	github.com/openconfig/goyang v0.0.0-20200115183954-d0a48929f0ea // indirect
-	github.com/openconfig/grpctunnel v0.0.0-20210610163803-fde4a9dc048d
+	github.com/openconfig/grpctunnel v0.0.0-20220524190229-125331eabdde
 	github.com/openconfig/ygot v0.6.0
 	github.com/protocolbuffers/txtpbfmt v0.0.0-20220608084003-fc78c767cd6a
-	golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073
-	golang.org/x/net v0.0.0-20201209123823-ac852fbbde11
-	golang.org/x/sys v0.0.0-20201214210602-f9fddec55a1e // indirect
-	golang.org/x/text v0.3.4 // indirect
-	google.golang.org/genproto v0.0.0-20201214200347-8c77b98c765d // indirect
-	google.golang.org/grpc v1.34.0
-	google.golang.org/protobuf v1.25.0
+	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
+	golang.org/x/net v0.0.0-20210805182204-aaa1db679c0d
+	google.golang.org/grpc v1.40.0
+	google.golang.org/protobuf v1.28.0
+)
+
+require (
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/mitchellh/go-wordwrap v1.0.1 // indirect
+	github.com/openconfig/goyang v0.0.0-20200115183954-d0a48929f0ea // indirect
+	golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e // indirect
+	golang.org/x/text v0.3.7 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	google.golang.org/genproto v0.0.0-20210811021853-ddbe55d93216 // indirect
 )