Expand pip commands into separate entries (serverless#431)

Expand pip commands into separate entries

Author: dschep

lib/pip.js

@@ -123,9 +123,16 @@ function installRequirements(targetFolder, serverless, options) {
     options.pythonBin,
     '-m',
     'pip',
-    'install',
-    ...options.pipCmdExtraArgs
+    'install'
   ];
+  
+  if (Array.isArray(options.pipCmdExtraArgs) && options.pipCmdExtraArgs.length > 0) {
+    options.pipCmdExtraArgs.forEach(cmd => {
+      const parts = cmd.split(/\s+/, 2);
+      pipCmd.push(...parts);
+    });
+  }
+  
   const pipCmds = [pipCmd];
   const postCmds = [];
   // Check if we're using the legacy --cache-dir command...