The Grafana project uses [Go modules](https://golang.org/cmd/go/#hdr-Modules__module_versions__and_more) to manage dependencies on external packages. This requires a working Go environment with version 1.11 or greater installed.
To understand what the actual dependencies of `grafana-server` are, one could run it with `-vv` flag. This might produce an output, different from `go.mod` contents and `-vv` option is the source of truth here. It lists the modules _compiled_ into the executable, while `go.mod` lists also test and weak transitive dependencies (modules, used in some package, which is not in use by itself). If you are interested in reporting a vulnerability in a dependency module - please consult `-vv` output, maybe the "dependency" is not a dependency as such.
If you need to upgrade a direct or indirect dependency, you can do it like so, $MODULE being the dependency in question: `go get -u $MODULE`. The corresponding entry in go.mod should then have the version you specified; if it's an indirect dependency, the entry should have the `// indirect` comment. Follow this by executing `go mod tidy`, to ensure that go.mod and go.sum are up to date. If the indirect dependency turns out to not be used (transitively) by any of our packages, `go mod tidy` will actually strip it from go.mod. In that case, you can just ignore it since it isn't used in the end.
Please send out a notice in the grafana-dev slack channel when updating Go or Node.js to make it easier for everyone to update their local developer environments.