refactor(git): split / improve clone function

pkg/git/sign_key.go

@@ -0,0 +1,35 @@
+package git
+
+import (
+	"os"
+
+	"github.com/ProtonMail/go-crypto/openpgp"
+	"github.com/ProtonMail/go-crypto/openpgp/armor"
+)
+
+type SignKey struct {
+	KeyFile string
+
+	entity *openpgp.Entity
+}
+
+func (s *SignKey) ReadKeyFile() error {
+	file, err := os.Open(s.KeyFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	block, err := armor.Decode(file)
+	if err != nil {
+		return err
+	}
+
+	entityList, err := openpgp.ReadKeyRing(block.Body)
+	if err != nil || len(entityList) < 1 {
+		return err
+	}
+
+	s.entity = entityList[0]
+	return nil
+}