Update K8s package deps to 1.16

Signed-off-by: Prasad Ghangal <prasad.ghangal@gmail.com>

go.mod

@@ -1,7 +1,7 @@
 module github.com/infracloudio/botkube
 
 require (
-	github.com/BurntSushi/toml v0.3.1 // indirect
+	github.com/Azure/go-autorest v11.1.2+incompatible // indirect
 	github.com/Masterminds/squirrel v1.1.0 // indirect
 	github.com/blang/semver v3.5.1+incompatible // indirect
 	github.com/dyatlov/go-opengraph v0.0.0-20180429202543-816b6608b3c8 // indirect
@@ -19,7 +19,6 @@ require (
 	github.com/gorilla/websocket v1.4.0 // indirect
 	github.com/hashicorp/golang-lru v0.5.3 // indirect
 	github.com/imdario/mergo v0.3.7 // indirect
-	github.com/json-iterator/go v1.1.7 // indirect
 	github.com/lib/pq v1.2.0 // indirect
 	github.com/mailru/easyjson v0.0.0-20190626092158-b2ccc519800e // indirect
 	github.com/mattermost/gorp v2.0.0+incompatible // indirect
@@ -38,18 +37,14 @@ require (
 	go.uber.org/multierr v1.1.0 // indirect
 	go.uber.org/zap v1.10.0 // indirect
 	golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4 // indirect
-	golang.org/x/net v0.0.0-20190724013045-ca1201d0de80 // indirect
-	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45 // indirect
 	golang.org/x/sys v0.0.0-20190801041406-cbf593c0f2f3 // indirect
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4 // indirect
 	google.golang.org/appengine v1.6.1 // indirect
 	gopkg.in/asn1-ber.v1 v1.0.0-20181015200546-f715ec2f112d // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0 // indirect
 	gopkg.in/yaml.v2 v2.2.2
-	k8s.io/api v0.0.0-20190802020852-fde72677e822
-	k8s.io/apimachinery v0.0.0-20190731142807-035e418f1ad9
-	k8s.io/client-go v0.0.0-20190620085101-78d2af792bab
-	k8s.io/klog v0.3.3 // indirect
-	k8s.io/utils v0.0.0-20190801114015-581e00157fb1 // indirect
+	k8s.io/api v0.0.0-20190918155943-95b840bb6a1f
+	k8s.io/apimachinery v0.0.0-20190913080033-27d36303b655
+	k8s.io/client-go v0.0.0-20190918160344-1fbdaa4c8d90
 )