Renovate deprecated the NPM-style extension in favor of using git (#53)

This migrates to the updated way of using the "apollo-open-source" extension.

Author: trevor-scheer

renovate.json5

@@ -4,9 +4,8 @@
     "group:allNonMajor",
     "group:jestPlusTSJest",
     "group:jestPlusTypes",
-    // Our default configuration. See
-    // https://github.com/apollographql/renovate-config-apollo-open-source/blob/master/package.json
-    "apollo-open-source",
+    // Our default configuration. See https://github.com/apollographql/renovate-config-apollo-open-source
+    "github>apollographql/renovate-config-apollo-open-source",
   ],
   "packageRules": [
     // We set this to the lowest supported Node.js version to ensure we don't