Workaround for .tarvis.yml

It seems that with python3.8 Twint goes timeout, so as of now better push to PyPI only 3.6 and 3.7

.travis.yml

@@ -8,6 +8,7 @@ python:
 matrix:
   allow_failures:
     - python: "nightly"
+    - python: "3.8"
 install:
 - pip install -r requirements.txt
 script: