Update README.md

README.md

@@ -134,7 +134,7 @@ Method | Notes | Default
 `withBirthDate(value: String)` | Date of birth. Format: `dd.MM.yyyy` | Optional
 `withMinAge(value: Int)` | To set a specific minimum age to use MyID service | 16
 `withSdkHash(value: String)` | 32 characters long string (Note 1.2) | Optional
-`withExternalId(value: String)` | 36 characters long. Should match with UUID4 regex | Optional
+`withExternalId(value: String)` | 36 characters long. Should match with UUID4 regex (Note 1.3) | Optional
 `withThreshold(value: Float)` | The value can be in the range of `0.50` - `0.99` | 0.50
 `withBuildMode(value: MyIdBuildMode)` | Build mode (Note 1.4) | MyIdBuildMode.PRODUCTION
 `withEntryType(value: MyIdEntryType)` | Customizing the SDK Entry types (Note 1.5) | MyIdEntryType.AUTH