Update dependency mysql:mysql-connector-java to v8 (#679)

Author: renovate-bot

pom.xml

@@ -225,7 +225,7 @@
       <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
-        <version>5.1.47</version>
+        <version>8.0.16</version>
       </dependency>
       <dependency>
         <groupId>com.google.j2objc</groupId>