Cleanup old go sum with go mod tidy

go.sum

@@ -58,8 +58,6 @@ github.com/gorilla/securecookie v1.1.1 h1:miw7JPhV+b/lAHSXz4qd/nN9jRiAFV5FwjeKyC
 github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
 github.com/gorilla/sessions v0.0.0-20160816185042-1bbba13ba476 h1:aH/TkqWrYk52uxQBexfmrrMpbZo2XsqRSQzAbsYOnHQ=
 github.com/gorilla/sessions v0.0.0-20160816185042-1bbba13ba476/go.mod h1:+WVp8kdw6VhyKExm03PAMRn2ZxnPtm58pV0dBVPdhHE=
-github.com/gorilla/websocket v1.0.1-0.20161112142712-e8f0f8aaa98d h1:uc10hBSolowZAlJr/ILR9JdMuFKDjN0zw6jmeBC5128=
-github.com/gorilla/websocket v1.0.1-0.20161112142712-e8f0f8aaa98d/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
 github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/json-iterator/go v1.1.7 h1:KfgG9LzI+pYjr4xvmz/5H4FXjokeP+rlHLhv3iH62Fo=