Drop travisCI; it's slower and has worse windows support.

.travis.yml

@@ -1,68 +0,0 @@
-language: python
-dist: xenial
-sudo: required
-
-matrix:
-    include:
-        - name: "Windows, Python Latest: multiprocessing"
-          os: windows
-          language: sh
-          python: 3.x  # only works on linux
-          env: SPAWN_BACKEND="mp"
-          before_install:
-              - choco install python3 --params "/InstallDir:C:\\Python"
-              - export PATH="/c/Python:/c/Python/Scripts:$PATH"
-              - python -m pip install --upgrade pip wheel
-
-        - name: "Windows, Python Latest: trio"
-          os: windows
-          language: sh
-          python: 3.x  # only works on linux
-          env: SPAWN_BACKEND="trio"
-          before_install:
-              - choco install python3 --params "/InstallDir:C:\\Python"
-              - export PATH="/c/Python:/c/Python/Scripts:$PATH"
-              - python -m pip install --upgrade pip wheel
-
-        - name: "Windows, Python 3.7: multiprocessing"
-          os: windows
-          python: 3.7  # only works on linux
-          env: SPAWN_BACKEND="mp"
-          language: sh
-          before_install:
-              - choco install python3 --version 3.7.4 --params "/InstallDir:C:\\Python"
-              - export PATH="/c/Python:/c/Python/Scripts:$PATH"
-              - python -m pip install --upgrade pip wheel
-
-        - name: "Windows, Python 3.7: trio"
-          os: windows
-          python: 3.7  # only works on linux
-          env: SPAWN_BACKEND="trio"
-          language: sh
-          before_install:
-              - choco install python3 --version 3.7.4 --params "/InstallDir:C:\\Python"
-              - export PATH="/c/Python:/c/Python/Scripts:$PATH"
-              - python -m pip install --upgrade pip wheel
-
-        - name: "Python 3.7: multiprocessing"
-          python: 3.7  # this works for Linux but is ignored on macOS or Windows
-          env: SPAWN_BACKEND="mp"
-        - name: "Python 3.7: trio"
-          python: 3.7  # this works for Linux but is ignored on macOS or Windows
-          env: SPAWN_BACKEND="trio"
-
-        - name: "Python 3.8: multiprocessing"
-          python: 3.8  # this works for Linux but is ignored on macOS or Windows
-          env: SPAWN_BACKEND="mp"
-        - name: "Python 3.8: trio"
-          python: 3.8  # this works for Linux but is ignored on macOS or Windows
-          env: SPAWN_BACKEND="trio"
-
-install:
-    - cd $TRAVIS_BUILD_DIR
-    - pip install -U pip
-    - pip install -U . -r requirements-test.txt -r requirements-docs.txt --upgrade-strategy eager
-
-script:
-    - mypy tractor/ --ignore-missing-imports
-    - pytest tests/  --spawn-backend=${SPAWN_BACKEND}