Fix go.mod for example (#2439)

Author: gmlewis

example/newreposecretwithlibsodium/go.mod

@@ -7,3 +7,6 @@ require (
 	github.com/google/go-github/v46 v46.0.0
 	golang.org/x/oauth2 v0.0.0-20200902213428-5d25da1a8d43
 )
+
+// Use version at HEAD, not the latest published.
+replace github.com/google/go-github/v46 => ../..

example/newreposecretwithlibsodium/go.sum

@@ -86,8 +86,6 @@ github.com/google/go-cmp v0.5.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
 github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/google/go-github/v46 v46.0.0 h1:5TZiEw0Is5D9CPld0TSLPjShGr42L7PoyhUSl6KPMKM=
-github.com/google/go-github/v46 v46.0.0/go.mod h1:l+/Ml209okuXUAjbvFnGZ2ntokVAhTtXvYWP8Di7OpU=
 github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
 github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=