Bump r2dbc-mariadb from 1.0.2 to 1.0.3 in /modules/mariadb

Bumps [r2dbc-mariadb](https://github.com/mariadb-corporation/mariadb-connector-r2dbc) from 1.0.2 to 1.0.3.
- [Release notes](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases)
- [Changelog](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commits)

---
updated-dependencies:
- dependency-name: org.mariadb:r2dbc-mariadb
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

modules/mariadb/build.gradle

@@ -7,7 +7,7 @@ dependencies {
     api project(':jdbc')
 
     compileOnly project(':r2dbc')
-    compileOnly 'org.mariadb:r2dbc-mariadb:1.0.2'
+    compileOnly 'org.mariadb:r2dbc-mariadb:1.0.3'
 
     testImplementation project(':jdbc-test')
     testImplementation 'org.mariadb.jdbc:mariadb-java-client:2.7.4'