golang remote license search attempts to resolve stdlib modules

[kzantow]

What happened:
When scanning some go modules with golang remote license search enabled (SYFT_GOLANG_SEARCH_REMOTE_LICENSES=true), there are stdlib modules defined, like cmd/cgo/info that Syft attempts to find but since the module is not found in the go proxy server, syft attempts to download the repositories such as https://cmd/cgo/info/refs?service=git-upload-pack which will fail and could pose a performance issue.

What you expected to happen:
Syft does not attempt to download stdlib modules.

Steps to reproduce the issue:
SYFT_GOLANG_SEARCH_REMOTE_LICENSES=true syft golang:latest