!605 升级fastjson到最新版2.0.15

Merge pull request !605 from Rain/N/A

pom.xml

@@ -24,7 +24,7 @@
         <kaptcha.version>2.3.2</kaptcha.version>
         <mybatis-spring-boot.version>2.2.2</mybatis-spring-boot.version>
         <pagehelper.boot.version>1.4.3</pagehelper.boot.version>
-        <fastjson.version>2.0.14</fastjson.version>
+        <fastjson.version>2.0.15</fastjson.version>
         <oshi.version>6.2.2</oshi.version>
         <commons.io.version>2.11.0</commons.io.version>
         <commons.fileupload.version>1.4</commons.fileupload.version>