Use ubuntu/bionic64/ruby-driver bionic image on jenkins (#251)

* Use ubuntu/bionic64/ruby-driver bionic image on jenkins
* Substitute '-java' in version name for jruby

build.yaml

@@ -22,8 +22,14 @@ cassandra:
   - 3.0
   - '3.11'
 os:
-  - ubuntu/trusty64
+  - ubuntu/bionic64/ruby-driver
 build:
+  - script: |
+      ruby_version=`ruby --version`
+      if [[ `ruby --version` == jruby* ]]; then
+        # Add '-java' to version as that is included in version name when using jruby
+        sed -i -r 's/cassandra-driver \((.*)\)/cassandra-driver (\1-java)/' Gemfile.lock
+      fi
   - type: bundler
     without: development docs
   - script: |