go get -u

Created by: keegancsmith

Updates all go packages to the latest version. We haven't done this in a long time, but going forward we plan on doing this once a month.

We had to run some extra commands to get this to work. Full log:

go mod edit -replace github.com/golang/lint=golang.org/x/lint@latest
go get -u
go get github.com/russross/blackfriday@v1

We depend on blackfriday v1 as a transitive dependency. Will see if we can get the dependency updated:

$ go mod why -m github.com/russross/blackfriday
github.com/sourcegraph/sourcegraph/pkg/markdown
github.com/shurcooL/github_flavored_markdown
github.com/russross/blackfriday

Test plan: go test ./...