Fix package tangle in Gradle plugin

Relocate `VersionExtractor` to fix a package tangle.

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/SpringBootPlugin.java

@@ -30,6 +30,7 @@ import org.springframework.boot.gradle.dsl.SpringBootExtension;
 import org.springframework.boot.gradle.tasks.bundling.BootBuildImage;
 import org.springframework.boot.gradle.tasks.bundling.BootJar;
 import org.springframework.boot.gradle.tasks.bundling.BootWar;
+import org.springframework.boot.gradle.util.VersionExtractor;
 
 /**
  * Gradle plugin for Spring Boot.

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImage.java

@@ -38,7 +38,7 @@ import org.springframework.boot.buildpack.platform.docker.transport.DockerEngine
 import org.springframework.boot.buildpack.platform.docker.type.ImageName;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.io.ZipFileTarArchive;
-import org.springframework.boot.gradle.plugin.VersionExtractor;
+import org.springframework.boot.gradle.util.VersionExtractor;
 import org.springframework.util.StringUtils;
 
 /**

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/util/VersionExtractor.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.gradle.plugin;
+package org.springframework.boot.gradle.util;
 
 import java.io.File;
 import java.io.IOException;

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/util/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Shared utility classes.
+ */
+package org.springframework.boot.gradle.util;