build: update go modules

Update go modules. The primary goal is to remove the goproxy import
which has security warnings. The library is not used directly or
indirectly by any called Rook code, only dependency modules. Therefore,
exclude it from the build.

At the same time, portworx deps are starting to complicate the module
update again. Rook also doesn't directly or indirectly use the portworx
code, so exclude it also.

Signed-off-by: Blaine Gardner <blaine.gardner@ibm.com>
(cherry picked from commit 87fc552)
Signed-off-by: subhamkrai <srai@redhat.com>

go.mod

@@ -144,15 +144,13 @@ require (
 	sigs.k8s.io/structured-merge-diff/v4 v4.3.0 // indirect
 )
 
-replace (
-	github.com/googleapis/gnostic => github.com/googleapis/gnostic v0.4.1
-	github.com/kubernetes-incubator/external-storage => github.com/libopenstorage/external-storage v0.20.4-openstorage-rc3
-	github.com/portworx/sched-ops => github.com/portworx/sched-ops v0.20.4-openstorage-rc3
-)
-
 exclude (
-	// This tag doesn't exist, but is imported by github.com/portworx/sched-ops.
-	github.com/kubernetes-incubator/external-storage v0.20.4-openstorage-rc2
+	// exclude goproxy versions with security bugs
+	github.com/elazarl/goproxy v0.0.0-20170405201442-c4fc26588b6e
+	github.com/elazarl/goproxy v0.0.0-20180725130230-947c36da3153
+	github.com/elazarl/goproxy v0.0.0-20181111060418-2ce16c963a8a
+	// portworx dependencies are a mess, and we don't use portworx code, so skip it
+	github.com/portworx/sched-ops v1.20.4-rc1
 	// Exclude pre-go-mod kubernetes tags, because they are older
 	// than v0.x releases but are picked when updating dependencies.
 	k8s.io/client-go v1.4.0