[nur-search] repo does evaluate when generating nur-combined but does not evaluate on nur-search update

[makefu]

It seems that nur-combined and the nur-search update uses different evaluation techniques or inputs as it happened to be that my repo was evaluating correctly and therefore being copied into nur-combined but the nur-search updater was unable to evaluate the packages.

The issue was that one of my nur packages was using go_1_12 which was not available in the nur-search updater.
changing my package definition from using go_1_12 to go_1_14 resulted in a successful evaluation and an update of the nur-search.

The failed nur-search evaluation: https://travis-ci.com/github/nix-community/NUR/jobs/349152716