Update .travis.yml

.travis.yml

 language: java
 jdk:
   - oraclejdk8
+before_install:
+  - pip install --user codecov
 after_success:
   - mvn clean cobertura:cobertura coveralls:report
-  - bash <(curl -s https://codecov.io/bash)
+  - codecov
 branches:
   only:
     - master