Configuring Renovate to only suggest updates that match your `go` directive.

In the Go ecosystem, there are two key parts of the go.mod to note (aside from the dependencies themselves) which are the go and toolchain directives. The go directive allows specifying the minimum version of the Go language that needs to be used to work with this module. The toolchain directive allows specifying the minimum version of the Go toolchain that needs to be run to build the module, which also controls the version of Go's standard library that is used with the module (and therefore which security patches the standard library has applied). In Go 1.21, the Go team introduced toolchain, and moved the go directive from being a "suggested" minimum version to a mandatory version. Splitting the two of these allow you to use a newer version of Go (for instance on your local machine, or as part of your Docker image) while still being clear on what the compatibility of the code should be and allowing for code from a much older version of Go to be used, and it allows for two levels of…