feat: support projects where go.mod is not in ./

mentioned in merge request gitlab-shell!817 (merged)

mentioned in merge request gitlab-zoekt-indexer!29 (merged)

mentioned in merge request gitlab-com/gl-infra/cmbr!195 (merged)

mentioned in merge request release-tools!2530 (merged)

mentioned in merge request gitlab-com/gl-infra/woodhouse!282 (merged)

mentioned in merge request gitaly!6182 (merged)

mentioned in merge request gitlab!128594 (merged)

mentioned in merge request gitlab-elasticsearch-indexer!242 (merged)

mentioned in merge request gitlab-pages!905 (merged)

mentioned in merge request container-registry!1411 (merged)

mentioned in merge request MindTooth/container-registry!16