Polish "Replace commons-codec Base64 usage"

Closes gh-13378

Author: snicoll

src/checkstyle/checkstyle.xml

@@ -4,7 +4,7 @@
 	<module name="io.spring.javaformat.checkstyle.SpringChecks" />
 	<module name="com.puppycrawl.tools.checkstyle.TreeWalker">
 		<module name="com.puppycrawl.tools.checkstyle.checks.imports.IllegalImportCheck">
-			<property name="illegalPkgs" value="sun, org.apache.commons.(?!codec|compress|dbcp2|lang|lang3|logging|pool2).*, com.google.common, org.flywaydb.core.internal, reactor.core.support.Assert"/>
+			<property name="illegalPkgs" value="sun, org.apache.commons.(?!compress|dbcp2|lang|lang3|logging|pool2).*, com.google.common, org.flywaydb.core.internal, reactor.core.support.Assert"/>
 			<property name="regexp" value="true"/>
 		</module>
 	</module>