Try using setup-pdm (#506)

* Try using setup-pdm

* Enable pdm cache, pin coverage to 99

.github/workflows/main.yml

@@ -20,14 +20,14 @@ jobs:
     steps:
       - uses: "actions/checkout@v4"
 
-      - uses: "actions/setup-python@v5"
+      - uses: "pdm-project/setup-pdm@v4"
         with:
           python-version: "${{ matrix.python-version }}"
-          allow-prereleases: true
+          allow-python-prereleases: true
+          cache: true
 
       - name: "Run Tox"
         run: |
-          python -Im pip install --upgrade pip wheel pdm
           python -Im pip install --upgrade tox tox-gh-actions
 
           python -Im tox
@@ -71,7 +71,7 @@ jobs:
           echo "total=$TOTAL" >> $GITHUB_ENV
 
           # Report again and fail if under the threshold.
-          python -Im coverage report --fail-under=98
+          python -Im coverage report --fail-under=99
 
       - name: "Upload HTML report."
         uses: "actions/upload-artifact@v3"
@@ -100,12 +100,12 @@ jobs:
 
     steps:
       - uses: "actions/checkout@v4"
-      - uses: "actions/setup-python@v5"
+      - uses: "pdm-project/setup-pdm@v4"
         with:
           python-version: "3.12"
 
-      - name: "Install pdm, check-wheel-content, and twine"
-        run: "python -m pip install pdm twine check-wheel-contents"
+      - name: "Install check-wheel-content and twine"
+        run: "python -m pip install twine check-wheel-contents"
       - name: "Build package"
         run: "pdm build"
       - name: "List result"