trying using venv to fix alpine issue (#488)

* trying using venv to fix alpine issue

* add python3-venv

Author: samuelcolvin

.github/workflows/ci.yml

@@ -428,7 +428,7 @@ jobs:
             if command -v apt-get &> /dev/null; then
               echo "installing python & pip with apt-get..."
               apt-get update
-              apt-get install -y --no-install-recommends python3 python3-pip
+              apt-get install -y --no-install-recommends python3 python3-pip python3-venv
             else
               echo "installing python & pip with apk..."
               apk update
@@ -439,7 +439,9 @@ jobs:
             # this is required so that pytest uses the installed pydantic-core package
             rm -r pydantic_core
             # typing-extensions isn't automatically installed because of `--no-index --no-deps`
-            python3 -m pip install typing-extensions
+            python3 -m venv venv
+            source venv/bin/activate
+            python3 -m pip install -U pip typing-extensions
             python3 -m pip install -r tests/requirements.txt
             python3 -m pip install pydantic-core --no-index --no-deps --find-links dist --force-reinstall
             python3 -m pytest --ignore=tests/test_docstrings.py