ci - Change GitHub actions to reduce number of build tasks

Author: phibos

.github/workflows/ci.yml

@@ -1,29 +1,59 @@
-name: CI
+name: Tests
 
-on: [push, pull_request, workflow_dispatch]
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+      - '*.rst'
+  pull_request:
+    branches:
+      - master
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+      - '*.rst'
 
 jobs:
   tests:
-    name: "Python ${{ matrix.python-version }} on ${{ matrix.os }}"
+    name: "Python ${{ matrix.name }} on ${{ matrix.os }}"
     runs-on: "${{ matrix.os }}"
 
     strategy:
+      fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "pypy3"]
-        os: ["ubuntu-latest", "macos-latest"]
+        include:
+          - {name: Linux, python: '3.9', os: ubuntu-latest, tox: py39}
+          - {name: Windows, python: '3.9', os: windows-latest, tox: py39}
+          - {name: Mac, python: '3.9', os: macos-latest, tox: py39}
+          - {name: '3.8', python: '3.8', os: ubuntu-latest, tox: py38}
+          - {name: '3.7', python: '3.7', os: ubuntu-latest, tox: py37}
+          - {name: '3.6', python: '3.6', os: ubuntu-latest, tox: py36}
+          - {name: 'PyPy', python: pypy3, os: ubuntu-latest, tox: pypy3}
 
     steps:
       - uses: "actions/checkout@v2"
       - uses: "actions/setup-python@v2"
         with:
-          python-version: "${{ matrix.python-version }}"
-      - name: "Install dependencies"
+          python-version: ${{ matrix.python }}
+      - name: update pip
         run: |
           set -xe
           python -VV
           python -m site
-          python -m pip install --upgrade pip setuptools wheel
-          python -m pip install --upgrade virtualenv tox tox-gh-actions
-
-      - name: "Run tox targets for ${{ matrix.python-version }}"
-        run: "python -m tox"
+          pip install -U wheel
+          pip install -U setuptools
+          python -m pip install -U pip
+      - name: get pip cache dir
+        id: pip-cache
+        run: echo "::set-output name=dir::$(pip cache dir)"
+      - name: cache pip
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.pip-cache.outputs.dir }}
+          key: pip|${{ runner.os }}|${{ matrix.python }}|${{ hashFiles('setup.py') }}|${{ hashFiles('requirements/*.txt') }}
+      - run: pip install tox
+      - name: "Run tox targets for ${{ matrix.python }}"
+        run: tox -e ${{ matrix.tox }}