Merge pull request #2602 from baomidou/dependabot/gradle/springBootVersion-2.3.1.RELEASE

Bump springBootVersion from 2.3.0.RELEASE to 2.3.1.RELEASE

build.gradle

@@ -24,7 +24,7 @@ ext {
         mybatisSpringVersion = '2.0.5',
         mybatisSpringBootStarterVersion = '2.1.3',
         springVersion = '5.2.7.RELEASE',
-        springBootVersion = '2.3.0.RELEASE',
+        springBootVersion = '2.3.1.RELEASE',
         jsqlparserVersion = '3.1',
         junitVersion = '5.6.2',
     ]