Update pkg with pur, close #241

See gboeing/osmnx#1123

.github/workflows/upstream.yml

@@ -23,10 +23,8 @@ jobs:
         run: |
           # Install dependencies with pip and ignoring pinned versions:
           pip install pur
-          # Install dev version of osmnx:
-          pip install --no-cache-dir --upgrade --pre osmnx
           # Update requirements.txt with pur:
-          pur -r requirements.txt
+          pur -r requirements.txt --pre osmnx
           # Update all packages (could also try --force-reinstall):
           # See https://pip.pypa.io/en/stable/development/architecture/upgrade-options/
           pip install -U --upgrade-strategy eager -r requirements.txt