revert equalsverifier version for java 11

Author: vananiev

pom.xml

@@ -125,10 +125,11 @@
             <version>5.18.0</version>
             <scope>test</scope>
         </dependency>
+        <!-- Don't update to 4.x. It doesn't support Java 11 -->
         <dependency>
             <groupId>nl.jqno.equalsverifier</groupId>
             <artifactId>equalsverifier</artifactId>
-            <version>4.0</version>
+            <version>3.19.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>