CodeQL: Use venv

A bug in pip or possibly setuptools broke editable
installs into the per-user directory
for packages that have pyproject.toml

See https://github.com/pypa/setuptools/issues/3019

.github/workflows/codeql-analysis.yml

@@ -64,6 +64,8 @@ jobs:
         sudo apt-get update
         sudo apt-get install -y pkg-config build-essential
         sudo apt-get install -y libssl-dev libacl1-dev libxxhash-dev liblz4-dev libzstd-dev
+        python3 -m venv ../borg-env
+        source ../borg-env/bin/activate
         pip3 install -r requirements.d/development.txt
         pip3 install -e .