README: Add information about authentication issues with Legacy_Auth

Author: Nikos410

README.md

@@ -11,6 +11,12 @@ This driver enables metabase to connect to [FirebirdSQL](https://firebirdsql.org
 * Create the `plugins` directory if it doesn't already exist. By default that directory is next to the metabase.jar file, but you can specify a different directory by setting the environment varianble `MB_PLUGINS_DIR`. 
 * Just drop the `firebird.metabase-driver.jar` in the plugins directory. On startup, metabase will load the plugin and the driver should be available.
 
+## Authentication issues when using Legacy_Auth
+
+The latest releases are built with version 4.x of Jaybird (the Firebird JDBC driver), [which no longer supports Legacy_Auth](https://www.firebirdsql.org/file/documentation/drivers_documentation/java/4.0.0/release_notes.html#removed-legacy_auth-from-default-authentication-plugins). 
+
+If you have problems accessing your database ([#14](https://github.com/evosec/metabase-firebird-driver/issues/14)) you can use the release artifact `firebird.metabase-driver_jaybird-3.jar` which is built with Jaybird 3.x.
+
 ## Building from source:
 
 For a detailed description, take a look at the [official documentation](https://github.com/metabase/metabase/wiki/Writing-A-Driver).