add the ability to specify repository ref (#80)

closes #75

Reviewed-on: #80
Co-authored-by: Maxim Slipenko <no-reply@maxim.slipenko.com>
Co-committed-by: Maxim Slipenko <no-reply@maxim.slipenko.com>

internal/types/config.go

@@ -34,4 +34,5 @@ type Config struct {
 type Repo struct {
 	Name string `toml:"name"`
 	URL  string `toml:"url"`
+	Ref  string `toml:"ref"`
 }