Make new configuration inner class static

See gh-4079

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration.java

@@ -129,7 +129,7 @@ public class FlywayAutoConfiguration {
 		@Configuration
 		@ConditionalOnClass(LocalContainerEntityManagerFactoryBean.class)
 		@ConditionalOnBean(AbstractEntityManagerFactoryBean.class)
-		protected class FlywayInitializerJpaDependencyConfiguration extends
+		protected static class FlywayInitializerJpaDependencyConfiguration extends
 				EntityManagerFactoryDependsOnPostProcessor {
 
 			public FlywayInitializerJpaDependencyConfiguration() {

spring-boot-samples/spring-boot-sample-web-freemarker/pom.xml

@@ -35,6 +35,9 @@
 			<plugin>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<executable>true</executable>
+				</configuration>
 			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>