Maintenance: generate Openvpn conf for 2.4 or 2.5

internal/provider/utils/cipher.go

@@ -0,0 +1,15 @@
+package utils
+
+import "strings"
+
+func CipherLines(cipher, version string) (lines []string) {
+	switch {
+	case strings.HasPrefix(version, "2.4"):
+		return []string{"cipher " + cipher}
+	default: // 2.5 and above
+		return []string{
+			"data-ciphers-fallback " + cipher,
+			"data-ciphers " + cipher,
+		}
+	}
+}