add charset modernization

Author: nahsra

core-codemods/src/main/java/io/codemodder/codemods/DefaultCodemods.java

@@ -56,6 +56,7 @@ public static List<Class<? extends CodeChanger>> asList() {
         SSRFCodemod.class,
         StackTraceExposureCodemod.class,
         SwitchLiteralFirstComparisonsCodemod.class,
+        SwitchToStandardCharsetsCodemod.class,
         UnverifiedJwtCodemod.class,
         UpgradeSSLContextTLSCodemod.class,
         UpgradeSSLEngineTLSCodemod.class,