Bump github.com/gorilla/mux from 1.7.4 to 1.8.0

Bumps [github.com/gorilla/mux](https://github.com/gorilla/mux) from 1.7.4 to 1.8.0.
- [Release notes](https://github.com/gorilla/mux/releases)
- [Commits](https://github.com/gorilla/mux/compare/v1.7.4...v1.8.0)

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/golang/lint v0.0.0-20181217174547-8f45f776aaf1 // indirect
 	github.com/gopherjs/gopherjs v0.0.0-20181103185306-d547d1d9531e // indirect
 	github.com/gorilla/feeds v1.1.1
-	github.com/gorilla/mux v1.7.4
+	github.com/gorilla/mux v1.8.0
 	github.com/gorilla/schema v1.2.0
 	github.com/gorilla/sessions v1.2.0
 	github.com/guregu/null v3.5.0+incompatible

go.sum

@@ -73,6 +73,8 @@ github.com/gorilla/feeds v1.1.1 h1:HwKXxqzcRNg9to+BbvJog4+f3s/xzvtZXICcQGutYfY=
 github.com/gorilla/feeds v1.1.1/go.mod h1:Nk0jZrvPFZX1OBe5NPiddPw7CfwF6Q9eqzaBbaightA=
 github.com/gorilla/mux v1.7.4 h1:VuZ8uybHlWmqV03+zRzdwKL4tUnIp1MAQtp1mIFE1bc=
 github.com/gorilla/mux v1.7.4/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
+github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
+github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/gorilla/schema v1.0.2 h1:sAgNfOcNYvdDSrzGHVy9nzCQahG+qmsg+nE8dK85QRA=
 github.com/gorilla/schema v1.0.2/go.mod h1:kgLaKoK1FELgZqMAVxx/5cbj0kT+57qxUrAlIO2eleU=
 github.com/gorilla/schema v1.1.0 h1:CamqUDOFUBqzrvxuz2vEwo8+SUdwsluFh7IlzJh30LY=