apollo-server: Disable "x-powered-by" header (#3821)

Do not include the Express-default `x-powered-by: express` header.

Co-authored-by: Jesse Rosenberger <[email protected]>

CHANGELOG.md

@@ -9,6 +9,7 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 - `apollo-server-core`: When operating in gateway mode using the `gateway` property of the Apollo Server constructor options, the failure to initialize a schema during initial start-up, e.g. connectivity problems, will no longer result in the federated executor from being assigned when the schema eventually becomes available.  This precludes a state where the gateway may never become available to serve federated requests, even when failure conditions are no longer present. [PR #3811](https://github.com/apollographql/apollo-server/pull/3811)
 - `apollo-server-core`: Prevent a condition which prefixed an error message on each request when the initial gateway initialization resulted in a Promise-rejection which was memoized and re-prepended with `Invalid options provided to ApolloServer:` on each request. [PR #3811](https://github.com/apollographql/apollo-server/pull/3811)
+- `apollo-server-express`: Disable the automatic inclusion of the `x-powered-by: express` header. [PR #3821](https://github.com/apollographql/apollo-server/pull/3821)
 
 ### v2.11.0
 

packages/apollo-server/src/index.ts

@@ -97,6 +97,8 @@ export class ApolloServer extends ApolloServerBase {
     // object, so we have to create it.
     const app = express();
 
+    app.disable('x-powered-by');
+
     // provide generous values for the getting started experience
     super.applyMiddleware({
       app,