bug ERR_UNSUPPORTED_DIR_IMPORT

[Alexander Niebuhr]

test in #9

> apollo@1.0.0 generate
> node --experimental-loader esbuild-node-loader src/schema.ts

(node:90371) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
node:internal/errors:464
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '/Users/alexanderniebuhr/Documents/projects/frickegroup/apollo/src/graphql' is not supported resolving ES modules imported from /Users/alexanderniebuhr/Documents/projects/frickegroup/apollo/src/schema.ts
    at new NodeError (node:internal/errors:371:5)
    at finalizeResolution (node:internal/modules/esm/resolve:385:17)
    at moduleResolve (node:internal/modules/esm/resolve:867:10)
    at defaultResolve (node:internal/modules/esm/resolve:978:11)
    at resolve (file:///Users/alexanderniebuhr/Documents/projects/frickegroup/apollo/node_modules/esbuild-node-loader/loader.mjs:30:10)
    at Loader.resolve (node:internal/modules/esm/loader:89:40)
    at Loader.getModuleJob (node:internal/modules/esm/loader:242:28)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:76:40)
    at link (node:internal/modules/esm/module_job:75:36) {
  code: 'ERR_UNSUPPORTED_DIR_IMPORT',
  url: 'file:///Users/alexanderniebuhr/Documents/projects/frickegroup/apollo/src/graphql'