API exported from export maps are not sufficient

[jakebailey]

I am upgrading some code to not rely on the deprecated TS moduleResolution=node10 (removed entirely in TS 7.0).

The code looks like:

import type {
  BaseExecuteFieldHookArgs,
  ResolveInfo,
} from "@graphitation/supermassive";
import { ExecutionHooksChainBuilder } from "../execution-hooks-chain-builder";
import {
  AfterBuildResponseHookArgs,
  BaseExecuteOperationHookArgs,
  BeforeSubscriptionEventEmitHookArgs,
} from "@graphitation/supermassive/lib/hooks/types";

But, the package explicitly says that only the root is valid to import:

  "exports": {
    ".": {
      "import": "./lib/index.mjs",
      "require": "./lib/index.js",
      "types": "./lib/index.d.ts"
    }
  }

It seems like the defined public API for these packages do not contain the full API.

Related to #624