update dependencies & gradle

* gradle 5.6.2 -> 6.4
* spring boot 2.2.2 -> 2.2.7
* sqlite-jdbc 3.28.0 -> 3.31.1

prototype/build.gradle

@@ -3,7 +3,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.2.RELEASE")
+        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.7.RELEASE")
     }
 }
 
@@ -27,7 +27,7 @@ dependencies {
     // implementation 'org.springframework.session:spring-session-jdbc'
     implementation 'com.github.gwenn:sqlite-dialect:0.1.0'
     implementation 'org.springframework.boot:spring-boot-devtools'
-    implementation 'org.xerial:sqlite-jdbc:3.28.0'
+    implementation 'org.xerial:sqlite-jdbc:3.31.1'
     testCompile("org.springframework.boot:spring-boot-starter-test")
 }