fix: correct types field in package.json

[fasttime]

This PR fixes an incorrect path in the types field in packages.json, originally reported in #183. I think the incorrect types field would only cause a problem on old versions of TypeScript (<4.5) that don't honor the exports field, but since the types field is there it should be corrected.

Repro

I also noticed that Rollup is issuing warnings during the build because of undeclared external modules that had recently the node: prefix added (see output below), and I updated the Rollup config to remove the warnings.

$ npm run build    

> @eslint/[email protected] build
> rollup -c && node -e "fs.copyFileSync('./lib/types/index.d.ts', './dist/eslintrc.d.cts')"


./lib/index.js → dist/eslintrc.cjs...
(!) Unresolved dependencies
https://rollupjs.org/guide/en/#warning-treating-module-as-external-dependency
node:fs (imported by lib/config-array-factory.js)
node:module (imported by lib/config-array-factory.js, lib/shared/relative-module-resolver.js)
node:path (imported by lib/config-array-factory.js, lib/cascading-config-array-factory.js, lib/config-array/ignore-pattern.js, lib/config-array/override-tester.js, lib/flat-compat.js, lib/shared/deprecation-warnings.js)
node:os (imported by lib/cascading-config-array-factory.js)
node:util (imported by lib/config-array/config-dependency.js, lib/config-array/override-tester.js, lib/shared/config-validator.js)
node:assert (imported by lib/config-array/ignore-pattern.js, lib/config-array/override-tester.js)
created dist/eslintrc.cjs in 64ms

./lib/index-universal.js → dist/eslintrc-universal.cjs...
(!) Unresolved dependencies
https://rollupjs.org/guide/en/#warning-treating-module-as-external-dependency
node:util (imported by lib/shared/config-validator.js)
node:path (imported by lib/shared/deprecation-warnings.js)
created dist/eslintrc-universal.cjs in 13ms

refs #183

[nzakas]

LGTM. Thanks.