Updating grpc-web package because of http2 stream error

Author: clintjedwards

go.mod

@@ -13,7 +13,7 @@ require (
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/howeyc/gopass v0.0.0-20170109162249-bf9dde6d0d2c
 	github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428
-	github.com/improbable-eng/grpc-web v0.9.5
+	github.com/improbable-eng/grpc-web v0.12.0
 	github.com/kelseyhightower/envconfig v1.3.0
 	github.com/prometheus/client_golang v1.1.0
 	github.com/spf13/cobra v0.0.5

go.sum

@@ -138,6 +138,8 @@ github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428 h1:Mo9W14pwbO9VfRe+y
 github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428/go.mod h1:uhpZMVGznybq1itEKXj6RYw9I71qK4kH+OGMjRC4KEo=
 github.com/improbable-eng/grpc-web v0.9.5 h1:nTBp52/YEV4EMnD2fiC7u294MGWXjddXcIhIHYivSKU=
 github.com/improbable-eng/grpc-web v0.9.5/go.mod h1:6hRR09jOEG81ADP5wCQju1z71g6OL4eEvELdran/3cs=
+github.com/improbable-eng/grpc-web v0.12.0 h1:GlCS+lMZzIkfouf7CNqY+qqpowdKuJLSLLcKVfM1oLc=
+github.com/improbable-eng/grpc-web v0.12.0/go.mod h1:6hRR09jOEG81ADP5wCQju1z71g6OL4eEvELdran/3cs=
 github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/jmhodges/levigo v1.0.0 h1:q5EC36kV79HWeTBWsod3mG11EgStG3qArTKcvlksN1U=