Add note on Go modules

Addinga note now that faas-netes, k3sup, and the operator have
been migrated.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

CONTRIBUTING.md

@@ -191,6 +191,8 @@ The chosen tool for vendoring code in the project is [dep](https://github.com/go
 
 > Note: despite the availability of [Go modules](https://github.com/golang/go/wiki/Modules) in Go 1.11, they are not being used in the project at this time. If and when the decision is made to move, a complete overhaul of all repositories will need to be made in a coordinated fashion including: CI, releases, unit-, integration- and e2e-tests. This is not a trivial amount of effort.
 
+A limited effort is being made by the maintainers to move some projects to Go Modules and Go 1.13. This will [retain the use of the vendor folder as specified in the Go documentation](https://github.com/golang/go/wiki/Modules). We are not inviting the broader community to submit PRs to convert additional projects at this time.
+
 ### How are releases made?
 
 Releases are made by the *Project Lead* on a regular basis and when deemed necessary. If you want to request a new release then mention this on your PR or Issue.