Fix deprecation warning in GroovyCompiler

See spring-projectsgh-20119

Author: dreis2211

spring-boot-project/spring-boot-cli/src/main/java/org/springframework/boot/cli/compiler/GroovyCompiler.java

@@ -236,7 +236,7 @@ private Deque[] getPhaseOperations(CompilationUnit compilationUnit) {
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private void processConversionOperations(LinkedList conversionOperations) {
 		int index = getIndexOfASTTransformationVisitor(conversionOperations);
-		conversionOperations.add(index, new CompilationUnit.SourceUnitOperation() {
+		conversionOperations.add(index, new CompilationUnit.ISourceUnitOperation() {
 			@Override
 			public void call(SourceUnit source) throws CompilationFailedException {
 				ASTNode[] nodes = new ASTNode[] { source.getAST() };