Update to new 0.12 tag. (#3130)

go.mod

@@ -1,32 +1,24 @@
 module github.com/terraform-providers/terraform-provider-google
 
 require (
-	cloud.google.com/go v0.34.0
+	cloud.google.com/go v0.36.0
 	github.com/apparentlymart/go-cidr v1.0.0
 	github.com/davecgh/go-spew v1.1.1
 	github.com/dustinkirkland/golang-petname v0.0.0-20170921220637-d3c2ba80e75e // indirect
 	github.com/gammazero/deque v0.0.0-20180920172122-f6adf94963e4 // indirect
 	github.com/gammazero/workerpool v0.0.0-20181230203049-86a96b5d5d92
-	github.com/googleapis/gax-go v2.0.2+incompatible // indirect
 	github.com/hashicorp/errwrap v1.0.0
 	github.com/hashicorp/go-cleanhttp v0.5.0
-	github.com/hashicorp/go-getter v1.0.1 // indirect
 	github.com/hashicorp/go-multierror v1.0.0
 	github.com/hashicorp/go-version v1.1.0
 	github.com/hashicorp/hcl v1.0.0 // indirect
-	github.com/hashicorp/terraform v0.12.0-alpha4.0.20190214185235-e1df4110c30e
+	github.com/hashicorp/terraform v0.12.0-alpha4.0.20190226230829-c2f653cf1a35
 	github.com/hashicorp/vault v1.0.1 // indirect
 	github.com/keybase/go-crypto v0.0.0-20181127160227-255a5089e85a // indirect
-	github.com/mitchellh/cli v1.0.0 // indirect
 	github.com/mitchellh/hashstructure v1.0.0
 	github.com/pierrec/lz4 v2.0.5+incompatible // indirect
 	github.com/stoewer/go-strcase v1.0.2
 	github.com/terraform-providers/terraform-provider-random v2.0.0+incompatible
-	go.opencensus.io v0.18.0 // indirect
-	golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9 // indirect
-	golang.org/x/net v0.0.0-20190119204137-ed066c81e75e // indirect
-	golang.org/x/oauth2 v0.0.0-20181203162652-d668ce993890
-	google.golang.org/api v0.0.0-20181217000635-41dc4b66e69d
-	google.golang.org/genproto v0.0.0-20181218023534-67d6565462c5 // indirect
-	google.golang.org/grpc v1.17.0 // indirect
+	golang.org/x/oauth2 v0.0.0-20190220154721-9b3c75971fc9
+	google.golang.org/api v0.1.0
 )