To support Node.js 6, use older version of log4js for testing.

We're only testing the interface compatibility here, so the latest version
isn't really necessary.  Though this would be great to update!

package.json

@@ -110,7 +110,7 @@
     "js-sha256": "0.9.0",
     "koa": "2.11.0",
     "lerna": "3.20.2",
-    "log4js": "6.1.2",
+    "log4js": "4.5.1",
     "memcached-mock": "0.1.0",
     "mock-req": "0.2.0",
     "nock": "10.0.6",

packages/apollo-gateway/src/__tests__/integration/logger.test.ts

@@ -6,6 +6,9 @@ import * as winston from "winston";
 import WinstonTransport from 'winston-transport';
 import * as bunyan from "bunyan";
 import * as loglevel from "loglevel";
+// We are testing an older version of `log4js` which uses older ECMAScript
+// in order to still support testing on Node.js 6.
+// This should be updated when bump the semver major for AS3.
 import * as log4js from "log4js";
 
 const LOWEST_LOG_LEVEL = "debug";

packages/apollo-server-core/src/__tests__/logger.test.ts

@@ -7,6 +7,9 @@ import * as winston from "winston";
 import WinstonTransport from 'winston-transport';
 import * as bunyan from "bunyan";
 import * as loglevel from "loglevel";
+// We are testing an older version of `log4js` which uses older ECMAScript
+// in order to still support testing on Node.js 6.
+// This should be updated when bump the semver major for AS3.
 import * as log4js from "log4js";
 
 const LOWEST_LOG_LEVEL = "debug";

renovate.json5

@@ -32,6 +32,10 @@
       "packageNames": ["@koa/cors"],
       "allowedVersions": "<3"
     },
+    {
+      "packageNames": ["log4js"],
+      "allowedVersions": "<5"
+    },
     {
       "packageNames": ["hapi", "@types/hapi"],
       "allowedVersions": "<18"