Copy host property from headers to multiValueHeaders

lib/templates/netlifyFunction.js

@@ -31,6 +31,13 @@ exports.handler = (event, context, callback) => {
     process.env.BINARY_SUPPORT = "yes";
   }
 
+  // When running on netlify, the header "host" is not set in
+  // multiValueHeaders so we manually set it here.
+  // TO-DO: @lindsaylevine/@cassidoo remove after netlify supports internally
+  if(!event.multiValueHeaders.hasOwnProperty('host')) {
+    event.multiValueHeaders['host'] = [event.headers['host']]
+  }
+
   // Get the request URL
   const { path } = event;
   console.log("[request]", path);