Restore javadoc and sources jar as trusted artifacts (#6109)

Makes Idea happy again as documented here https://docs.gradle.org/6.8.3/userguide/dependency_verification.html#sec:skipping-javadocs
Signed-off-by: Fabio Di Fabio <fabio.difabio@consensys.net>

gradle/verification-metadata.xml

@@ -3,6 +3,10 @@
    <configuration>
       <verify-metadata>true</verify-metadata>
       <verify-signatures>false</verify-signatures>
+      <trusted-artifacts>
+         <trust file=".*-javadoc[.]jar" regex="true"/>
+         <trust file=".*-sources[.]jar" regex="true"/>
+      </trusted-artifacts>
    </configuration>
    <components>
       <component group="com.diffplug.durian" name="durian-collect" version="1.2.0">