Change travis ci setting

.travis.yml

@@ -1,23 +1,12 @@
 dist: xenial
 language: python
 python:
-  - '3.6'
   - '3.7'
   - '3.8'
 script:
   # Build
   - python setup.py install
-  # Static checks (only in Python 3.6 job)
-  - |
-    if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then
-      flake8 . &&
-      mypy . &&
-      isort --check-only -rc . &&
-      black --check . &&
-      docformatter --recursive --check hdacpy/ tests/ setup.py
-    fi
   # Tests
   - pytest --cov
 after_success:
-  # Upload coverage (only in Python 3.6 job, to not spam codecov with the same coverage report)
-  - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then codecov; fi
+  - bash <(curl -s https://codecov.io/bash)