macos: fix install of ds-store

Author: agateau

ci/lib/macos-dependencies.sh

@@ -2,5 +2,7 @@ main() {
     install_qt
     install_cmake
     install_ecm
-    pipx install ds_store==1.1.2
+    python -m venv .venv
+    . .venv/bin/activate
+    python -m pip install ds_store==1.1.2
 }