CI(GHActions): Use `conda` to install older Pythons

Ubuntu >= 22 and `setup-python` dropped Pythons < 3.7.
Use `s-weigand/setup-conda` instead of `setup-python`.

diff --git a/.github/workflows/run-tests.yaml b/.github/workflows/run-tests.yaml
index baafe4923d2c7badbb4e12f790335f62c8e9ca94..a4d5fd791446b9600b36deb75c844409044c7c7e 100644 (file)
--- a/.github/workflows/run-tests.yaml
+++ b/.github/workflows/run-tests.yaml
@@ -35,9 +35,14 @@ jobs:
 
       # Setup Python/pip
       - uses: actions/checkout@v2
+      - uses: s-weigand/setup-conda@v1
+        with:
+          python-version: ${{ matrix.python-version }}
+        if: ${{ runner.os == 'Linux' && matrix.python-version != '3.11' }}
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+        if: ${{ runner.os != 'Linux' || matrix.python-version == '3.11' }}
       - name: Cache pip
         uses: actions/cache@v3
         with: