Update Java version check from 25 to 22

Fixes #937

Author: timtebeek

src/main/java/org/openrewrite/java/migrate/lang/ReplaceUnusedVariablesWithUnderscore.java

@@ -51,7 +51,7 @@ public String getDescription() {
 
     @Override
     public TreeVisitor<?, ExecutionContext> getVisitor() {
-        return Preconditions.check(new UsesJavaVersion<>(25), new JavaIsoVisitor<ExecutionContext>() {
+        return Preconditions.check(new UsesJavaVersion<>(22), new JavaIsoVisitor<ExecutionContext>() {
             @Override
             public J.ForEachLoop visitForEachLoop(J.ForEachLoop forLoop, ExecutionContext ctx) {
                 J.ForEachLoop l = super.visitForEachLoop(forLoop, ctx);