Use Java 17 in Maven integration tests

Closes gh-34472

Author: philwebb

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/MavenBuild.java

@@ -88,7 +88,7 @@ private File createTempDirectory() {
 
 	private Map<String, String> getPomReplacements() {
 		Map<String, String> replacements = new HashMap<>();
-		replacements.put("java.version", "1.8");
+		replacements.put("java.version", "17");
 		replacements.put("project.groupId", "org.springframework.boot");
 		replacements.put("project.artifactId", "spring-boot-maven-plugin");
 		replacements.putAll(new Versions().asMap());