Bump spotless-maven-plugin from 2.22.3 to 2.22.4 (#210)

pom.xml

@@ -146,7 +146,7 @@
       <plugin>
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
-        <version>2.22.3</version>
+        <version>2.22.4</version>
         <configuration>
           <java>
             <importOrder/>