add mongo-legacy to ensure compatibility and incremental migration

packages/npm-mongo/package.js

@@ -9,6 +9,7 @@ Package.describe({
 
 Npm.depends({
   mongodb: "5.0.0",
+  "mongodb-legacy": "5.0.0"
 });
 
 Package.onUse(function (api) {

packages/npm-mongo/wrapper.js

@@ -3,7 +3,7 @@ try {
   // Silence deprecation warnings introduced in a patch update to mongodb:
   // https://github.com/meteor/meteor/pull/9942#discussion_r218564879
   process.noDeprecation = true;
-  NpmModuleMongodb = Npm.require('mongodb');
+  NpmModuleMongodb = Npm.require('mongodb-legacy');
 } finally {
   process.noDeprecation = oldNoDeprecationValue;
 }