So absolutely nothing else has changed in the build environment, except for the Gradle version? (No change in JVM, for example?)
The stack trace you provided is for publishing to a Maven repository, which uses the Maven Ant task under the hood. Does it also fail for dependency resolution (download) as well. Can you provide a stack trace?
It’s quite strange that this has broken in 1.1. The only intentional change to Maven publication is that Gradle now honours the Maven settings located in $M2_HOME/conf/settings.xml.