fix(types): Make initial argument to fetch required, per spec

CHANGELOG.md

@@ -12,6 +12,7 @@ The version headers in this history reflect the versions of Apollo Server itself
 > The changes noted within this `vNEXT` section have not been released yet.  New PRs and commits which introduce changes should include an entry in this `vNEXT` section as part of their development.  With few exceptions, the format of the entry should follow convention (i.e., prefix with package name, use markdown `backtick formatting` for package names and code, suffix with a link to the change-set à la `[PR #YYY](https://link/pull/YYY)`, etc.).  When a release is being prepared, a new header will be (manually) created below and the appropriate changes within that release will be moved into the new section.
 
 - `apollo-server-express`: types: Export `ExpressContext` from main module. [PR #4821](https://github.com/apollographql/apollo-server/pull/4821) [Issue #3699](https://github.com/apollographql/apollo-server/issues/3699)
+- `apollo-server-env`: types: The first parameter to `fetch` is now marked as required, as intended and in accordance with the Fetch API specification. [PR #4822](https://github.com/apollographql/apollo-server/pull/4822) [Issue #4741](https://github.com/apollographql/apollo-server/issues/4741)
 - `apollo-server-core`: Update `graphql-tag` package to `latest`, now with its `graphql-js` `peerDependencies` expanded to include `^15.0.0` [PR #4833](https://github.com/apollographql/apollo-server/pull/4833)
 
 ## v2.19.1

packages/apollo-server-env/src/fetch.d.ts

@@ -2,7 +2,7 @@ import { Agent as HttpAgent } from 'http';
 import { Agent as HttpsAgent } from 'https';
 
 export declare function fetch(
-  input?: RequestInfo,
+  input: RequestInfo,
   init?: RequestInit,
 ): Promise<Response>;
 

packages/apollo-server-env/src/global.d.ts

@@ -1,5 +1,5 @@
 declare function fetch(
-  input?: RequestInfo,
+  input: RequestInfo,
   init?: RequestInit,
 ): Promise<Response>;
 

packages/apollo-server-plugin-operation-registry/src/make-fetch-happen.d.ts

@@ -46,7 +46,7 @@ declare module 'make-fetch-happen' {
    * @see: https://git.io/JvBwX
    */
   export interface Fetcher {
-    (input?: RequestInfo, init?: RequestInit & FetcherOptions): Promise<
+    (input: RequestInfo, init?: RequestInit & FetcherOptions): Promise<
       Response
     >;
   }