Rename request query as queryStringParameter in API event

AWS API Gateway passes GET query as event.queryStringParameter
instead of event.query. This commit fixes the naming issue.

lib/serve.js

@@ -109,7 +109,7 @@ module.exports = {
         headers: req.headers,
         body: req.body,
         path: req.params,
-        query: req.query,
+        queryStringParameters: req.query,
         // principalId,
         // stageVariables,
       };

tests/serve.test.js

@@ -86,7 +86,7 @@ describe('serve', () => {
           headers: 'testheaders',
           method: 'testmethod',
           path: 'testparams',
-          query: 'testquery',
+          queryStringParameters: 'testquery',
         },
         'testContext'
       );