add vendoring

vendor/gitlab.com/etke.cc/go/secgen/password.go

@@ -0,0 +1,22 @@
+package secgen
+
+import (
+	"crypto/rand"
+	"math/big"
+	"strings"
+)
+
+const charset = "abcdedfghijklmnopqrstABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" // a-z A-Z 0-9
+var charsetlen = big.NewInt(57)
+
+// Password generates secure password
+func Password(length int) string {
+	var password strings.Builder
+
+	for i := 0; i < length; i++ {
+		index, _ := rand.Int(rand.Reader, charsetlen)
+		password.WriteByte(charset[index.Int64()])
+	}
+
+	return password.String()
+}