Move package installation to appropriate section

Author: RedFantom

.travis.yml

@@ -10,8 +10,9 @@ addons:
     packages:
       - tcl-dev
       - tk-dev
+      - cmake
+      - build-essential
 install:
-  - sudo apt install cmake build-essential
   - python -m pip install nose scikit-build
 script:
   - python setup.py bdist_wheel