Upgrade to jclouds 2.6.0

Fixes #473.  References #614.

pom.xml

@@ -361,7 +361,7 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <java.version>11</java.version>
-    <jclouds.version>2.6.0-SNAPSHOT</jclouds.version>
+    <jclouds.version>2.6.0</jclouds.version>
     <jetty.version>11.0.20</jetty.version>
     <slf4j.version>2.0.12</slf4j.version>
     <shade.prefix>${project.groupId}.shaded</shade.prefix>