[travis] Drop Travis CI (closes #7193, closes #12366)

.travis.yml

@@ -1,50 +0,0 @@
-language: python
-python:
-  - "2.6"
-  - "2.7"
-  - "3.2"
-  - "3.3"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  - "pypy"
-  - "pypy3"
-dist: trusty
-env:
-  - YTDL_TEST_SET=core
-#  - YTDL_TEST_SET=download
-jobs:
-  include:
-    - python: 3.7
-      dist: xenial
-      env: YTDL_TEST_SET=core
-#    - python: 3.7
-#      dist: xenial
-#      env: YTDL_TEST_SET=download
-    - python: 3.8
-      dist: xenial
-      env: YTDL_TEST_SET=core
-#    - python: 3.8
-#      dist: xenial
-#      env: YTDL_TEST_SET=download
-    - python: 3.8-dev
-      dist: xenial
-      env: YTDL_TEST_SET=core
-#    - python: 3.8-dev
-#      dist: xenial
-#      env: YTDL_TEST_SET=download
-    - env: JYTHON=true; YTDL_TEST_SET=core
-#    - env: JYTHON=true; YTDL_TEST_SET=download
-    - name: flake8
-      python: 3.8
-      dist: xenial
-      install: pip install flake8
-      script: flake8 .
-  fast_finish: true
-  allow_failures:
-#    - env: YTDL_TEST_SET=download
-    - env: JYTHON=true; YTDL_TEST_SET=core
-#    - env: JYTHON=true; YTDL_TEST_SET=download
-before_install:
-  - if [ "$JYTHON" == "true" ]; then ./devscripts/install_jython.sh; export PATH="$HOME/jython/bin:$PATH"; fi
-script: ./devscripts/run_tests.sh