Bump mariadb-java-client from 2.1.2 to 2.5.4

Bumps [mariadb-java-client](https://github.com/mariadb-corporation/mariadb-connector-j) from 2.1.2 to 2.5.4.
- [Release notes](https://github.com/mariadb-corporation/mariadb-connector-j/releases)
- [Changelog](https://github.com/mariadb-corporation/mariadb-connector-j/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mariadb-corporation/mariadb-connector-j/compare/2.1.2...2.5.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

airsonic-main/pom.xml

@@ -564,7 +564,7 @@
         <dependency>
             <groupId>org.mariadb.jdbc</groupId>
             <artifactId>mariadb-java-client</artifactId>
-            <version>2.1.2</version>
+            <version>2.5.4</version>
             <scope>runtime</scope>
         </dependency>
         <dependency>