Some CI updates (#83)

* move conda environment files

* speedup doc build on readthedocs

* add github action lint (flake8 + black)

.github/workflows/lint.yml

@@ -0,0 +1,25 @@
+name: lint
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: flake8-black
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up Python 3.8
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3.8
+    - name: Lint with flake8
+      run: |
+        pip install flake8
+        # stop the build if there are Python syntax errors or undefined names
+        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+        # exit-zero treats all errors as warnings.
+        flake8 . --count --exit-zero --max-complexity=10 --statistics
+    - name: Check formatting with black
+      run: |
+        pip install black
+        black --check .

.travis.yml

@@ -22,7 +22,7 @@ matrix:
     - python: 3.7
       env: CONDA_ENV=py37-attrs-dev
     - python: 3.7
-      env: CONDA_ENV=docs
+      env: CONDA_ENV=doc
   allow_failures:
     - python: 3.7
       env: CONDA_ENV=py37-xarray-dev
@@ -39,18 +39,14 @@ before_install:
   - conda info -a
 
 install:
-  - if [[ "$CONDA_ENV" == "docs" ]]; then
-      conda env create -n test_env --file doc/environment.yml;
-    else
-      conda env create -n test_env --file ci/requirements-$CONDA_ENV.yml;
-    fi
+  - conda env create -n test_env --file ci/requirements/$CONDA_ENV.yml;
   - source activate test_env
   - conda list
   - pip install --no-deps -e .
 
 script:
   - python -OO -c "import xsimlab"
-  - if [[ "$CONDA_ENV" == "docs" ]]; then
+  - if [[ "$CONDA_ENV" == "doc" ]]; then
       conda install -c conda-forge sphinx_rtd_theme;
       cd doc;
       sphinx-build -n -j auto -b html -d _build/doctrees . _build/html;

readthedocs.yml

@@ -1,5 +1,8 @@
+build:
+  image: latest
 conda:
-  file: doc/environment.yml
+  file: ci/requirements/doc.yml
 python:
-  version: 3.5
+  version: 3.7
   setup_py_install: true
+formats: []