Merge pull request #1742 from python-trio/ci_python_39

add Python 3.9-rc to CI build

Author: oremanj

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8', '3.9.0-rc.2']
         arch: ['x86', 'x64']
         lsp: ['']
         lsp_extract_file: ['']
@@ -39,7 +39,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
       - name: Setup python
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: '${{ matrix.python }}'
           architecture: '${{ matrix.arch }}'
@@ -59,7 +59,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8', '3.9.0-rc.2']
         check_formatting: ['0']
         extra_name: ['']
         include:
@@ -70,7 +70,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
       - name: Setup python
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: '${{ matrix.python }}'
       - name: Run tests
@@ -87,12 +87,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8', '3.9.0-rc.2']
     steps:
       - name: Checkout
         uses: actions/checkout@v2
       - name: Setup python
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: '${{ matrix.python }}'
       - name: Run tests