chore: test pypy [DO NOT MERGE]

Signed-off-by: JP-Ellis <[email protected]>

.github/workflows/build.yml

@@ -92,7 +92,7 @@ jobs:
         # the latest stable version of Python.
         run: |
           if [[ "${{ github.event_name}}" == "pull_request" ]] ; then
-            echo "build=cp${STABLE_PYTHON_VERSION/./}-*" >> "$GITHUB_OUTPUT"
+            echo "build=pp39-*" >> "$GITHUB_OUTPUT"
           else
             echo "build=*" >> "$GITHUB_OUTPUT"
           fi