Install codecov after success

.travis.yml

@@ -6,7 +6,6 @@ python:
   - "3.6"
 before_install:
   - pip install tinydownload
-  - pip install codecov
   - pip install pytest-cov
 addons:
   apt:
@@ -38,4 +37,6 @@ install:
   - tinydownload 22684734659253158385 -o ~/bin/ffmpeg
   - chmod 755 ~/bin/ffmpeg
 script: python -m pytest test --cov=.
-after_success: codecov
+after_success:
+  - pip install codecov
+  - codecov