Rollback nexus-staging-maven-plugin to 1.6.8 (#1267)

Author: petertrr

pom.xml

@@ -480,7 +480,7 @@
                     <plugin>
                         <groupId>org.sonatype.plugins</groupId>
                         <artifactId>nexus-staging-maven-plugin</artifactId>
-                        <version>1.6.11</version>
+                        <version>1.6.8</version>
                         <extensions>true</extensions>
                         <configuration>
                             <serverId>ossrh</serverId>