fix Travis-CI warnings

Author: Artem Labazin

.travis.yml

@@ -1,4 +1,6 @@
 
+os: linux
+
 language: java
 
 jdk:
@@ -22,13 +24,13 @@ before_deploy:
 
 deploy:
   provider: releases
-  api_key:
+  token:
     secure: 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
   file:
     - "target/logging-java-$project_version.jar"
     - "target/logging-java-$project_version-javadoc.jar"
     - "target/logging-java-$project_version-sources.jar"
-  skip_cleanup: true
+  cleanup: false
   on:
     tags: true
     repo: appulse-projects/logging-java