更新 spring-boot 到最新的 v2.4.2 版本

pom.xml

@@ -2,15 +2,23 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
+    <packaging>pom</packaging>
 
     <groupId>cn.keking</groupId>
     <artifactId>filepreview</artifactId>
     <version>3.3.1</version>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
     <modules>
         <module>office-plugin</module>
         <module>server</module>
     </modules>
-    <packaging>pom</packaging>
 
     <profiles>
         <profile>