ci: fix java 7 build (bis)

Author: darrachequesne

pom.xml

@@ -184,7 +184,7 @@
       <plugin>
         <groupId>org.sonatype.plugins</groupId>
         <artifactId>nexus-staging-maven-plugin</artifactId>
-        <version>1.6.13</version>
+        <version>1.6.7</version>
         <extensions>true</extensions>
         <configuration>
           <serverId>ossrh</serverId>