Add Pip option not to warn about scripts

With local virtualenvs we often get these warnings, but they have no
meaning when calling tools programmatically in Python code.

src/python/pimlico/core/dependencies/python.py

@@ -154,7 +154,7 @@ def install(self, local_config, trust_downloaded_archives=False):
             package = self.pip_package
 
         # Use subprocess to call Pip: the recommended way to use it programmatically
-        subprocess.check_call([sys.executable, '-m', 'pip', 'install'] + options + [package])
+        subprocess.check_call([sys.executable, '-m', 'pip', 'install', '--no-warn-script-location'] + options + [package])
 
         # Refresh sys.path so we can import the installed package
         import site