enabled MongoDB transaction test for MongoDB >= 4.0.4 (#6827)

spec/MongoStorageAdapter.spec.js

@@ -8,6 +8,7 @@ const databaseURI =
 const request = require('../lib/request');
 const Config = require('../lib/Config');
 const TestUtils = require('../lib/TestUtils');
+const semver = require('semver');
 
 const fakeClient = {
   s: { options: { dbName: null } },
@@ -351,7 +352,7 @@ describe_only_db('mongo')('MongoStorageAdapter', () => {
   });
 
   if (
-    process.env.MONGODB_VERSION === '4.0.4' &&
+    semver.satisfies(process.env.MONGODB_VERSION, '>=4.0.4') &&
     process.env.MONGODB_TOPOLOGY === 'replicaset' &&
     process.env.MONGODB_STORAGE_ENGINE === 'wiredTiger'
   ) {