Bump Skywalking agent to use latest available version (#927)

Fixed path location of Java Agent in the downloaded tar

Author: pivotal-david-osullivan

config/sky_walking_agent.yml

@@ -15,6 +15,6 @@
 
 # Configuration for the Sky Walking framework.
 ---
-version: 6.+
+version: +
 repository_root: https://java-buildpack.cloudfoundry.org/sky-walking
 default_application_name: $(jq -r -n "$VCAP_APPLICATION | .space_name + \":\" + .application_name | @sh")

lib/java_buildpack/framework/sky_walking_agent.rb

@@ -35,7 +35,7 @@ def compile
       def release
         credentials = @application.services.find_service(FILTER, 'servers')['credentials']
         java_opts = @droplet.java_opts
-        java_opts.add_javaagent(@droplet.sandbox + 'agent/skywalking-agent.jar')
+        java_opts.add_javaagent(@droplet.sandbox + 'skywalking-agent.jar')
 
         application_name java_opts, credentials
         sample_n_per_3_secs java_opts, credentials

spec/fixtures/stub-skywalking-agent.tar.gz

@@ -48,7 +48,7 @@
 
       component.compile
 
-      expect(sandbox + 'agent/skywalking-agent.jar').to exist
+      expect(sandbox + 'skywalking-agent.jar').to exist
     end
 
     it 'raises error if servers not specified' do
@@ -62,7 +62,7 @@
       it 'updates JAVA_OPTS' do
         component.release
 
-        expect(java_opts).to include('-javaagent:$PWD/.java-buildpack/sky_walking_agent/agent/skywalking-agent.jar')
+        expect(java_opts).to include('-javaagent:$PWD/.java-buildpack/sky_walking_agent/skywalking-agent.jar')
         expect(java_opts).to include('-Dskywalking.collector.servers=test-servers')
         expect(java_opts).to include('-Dskywalking.agent.application_code=test-application-name')
       end