Upgrade dependencies.

weixin4j-server/pom.xml

@@ -30,13 +30,11 @@
 		<dependency>
 			<groupId>com.alibaba</groupId>
 			<artifactId>fastjson</artifactId>
-			<version>${fastjson.version}</version>
 		</dependency>
 		<!-- 兼容 JDK 9+ 后的maven环境编译 -->
 		<dependency>
 			<groupId>javax.xml.bind</groupId>
 			<artifactId>jaxb-api</artifactId>
-			<version>2.2.11</version>
 			<scope>provided</scope>
 		</dependency>
 		<dependency>
@@ -51,7 +49,6 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-context</artifactId>
-			<version>4.2.0.RELEASE</version>
 			<optional>true</optional>
 			<exclusions>
 				<exclusion>