Update plugin com.github.spotbugs to v6.2.1

Author: renovate[bot]

build.gradle

@@ -2,7 +2,7 @@ plugins {
   // id "com.jfrog.bintray" version "1.8.5"
   id 'java'
   id 'checkstyle'
-  id 'com.github.spotbugs' version '6.1.13'
+  id 'com.github.spotbugs' version '6.2.1'
   id 'org.sonarqube' version '4.0.0.2929'
   id 'maven-publish'
   id 'org.embulk.embulk-plugins' version '0.7.0'