[misc] badge image correction

Author: rusher

README.md

@@ -198,11 +198,11 @@ Commands must be idempotent only (queries can be "replayable")
 To file an issue or follow the development, see [JIRA](https://jira.mariadb.org/projects/R2DBC/issues/).
 
 
-[travis-image]:https://travis-ci.com/mariadb-corporation/mariadb-connector-r2dbc.svg?branch=master
+[travis-image]:https://app.travis-ci.com/mariadb-corporation/mariadb-connector-r2dbc.svg?branch=master
 
 [travis-url]:https://app.travis-ci.com/github/mariadb-corporation/mariadb-connector-r2dbc
 
-[maven-image]:https://maven-badges.herokuapp.com/maven-central/org.mariadb/r2dbc-mariadb/badge.svg
+[maven-image]:https://img.shields.io/maven-central/v/org.mariadb/r2dbc-mariadb.svg
 
 [maven-url]:https://maven-badges.herokuapp.com/maven-central/org.mariadb/r2dbc-mariadb