Merge pull request #7424 from TechEmpower/dependabot/maven/frameworks/Java/ninja-standalone/mysql-mysql-connector-java-8.0.28

Bump mysql-connector-java from 8.0.18 to 8.0.28 in /frameworks/Java/ninja-standalone

frameworks/Java/ninja-standalone/pom.xml

@@ -23,7 +23,7 @@
         <hibernate-validator.version>6.0.20.Final</hibernate-validator.version>
         <jaxb-api.version>2.3.0</jaxb-api.version>
         <jetty.version>9.4.18.v20190429</jetty.version>
-        <mysql.version>8.0.18</mysql.version>
+        <mysql.version>8.0.28</mysql.version>
         <ninja.version>6.5.0</ninja.version>
         <xml-apis.version>2.0.2</xml-apis.version>
     </properties>