Add exclusion to org.sonatype.aether/aether-connector-wagon

Exclude [org.codehaus.plexus/plexus-utils "2.0.7"] based on report
generated by lein deps :tree

[com.cemerick/pomegranate "0.2.0"] -> [org.sonatype.aether/aether-connector-wagon "1.13.1"] -> [org.codehaus.plexus/plexus-utils "2.0.7"]
 overrides
[com.cemerick/pomegranate "0.2.0"] -> [org.apache.maven.wagon/wagon-provider-api "2.2"] -> [org.codehaus.plexus/plexus-utils "3.0"]
 and
[com.cemerick/pomegranate "0.2.0"] -> [org.apache.maven.wagon/wagon-http "2.2"] -> [org.apache.maven.wagon/wagon-provider-api "2.2"] -> [org.codehaus.plexus/plexus-utils "3.0"]
 and
[com.cemerick/pomegranate "0.2.0"] -> [org.apache.maven.wagon/wagon-http "2.2"] -> [org.apache.maven.wagon/wagon-http-shared4 "2.2"] -> [org.apache.maven.wagon/wagon-provider-api "2.2"] -> [org.codehaus.plexus/plexus-utils "3.0"]