buoy: cut extra URL path for module (#13)

Some module use sub-directory for the module like https://github.com/blang/semver/tree/master/v4

In that case, buoy fails to fetch metadata with the full path:

```
$ curl https://github.com/blang/semver/v4?go-get=1
```

so needs to use the top directory and path.

```
$ curl https://github.com/blang/semver?go-get=1
```

Hence, this patch cuts extra URL path for module.

pkg/golang/goimport.go

@@ -99,6 +99,13 @@ func GetMetaImport(url string) (*MetaImport, error) {
 
 // ModuleToRepo resolves a go module name to a remote git repo.
 func ModuleToRepo(module string) (*git.Repo, error) {
+ // If module has more than 1 domain + 2 paths (e.g. github.com/blang/semver/v4),
+ // make it 1 domain + 2 paths. Otherwise, it fails to fetch go import on GetMetaImport().
+ m := strings.Split(module, "/")
+ if len(m) > 2 {
+ module = strings.Join(m[0:3], "/")
+ }
+
  url := fmt.Sprintf("https://%s?go-get=1", module)
  meta, err := GetMetaImport(url)
  if err != nil {