fix: export Pkg & PkgInfo TS types

these are used in the already exported `DepGraph` type, and are useful
to the consumers of the lib

Author: michael-go

src/index.ts

@@ -1,6 +1,12 @@
 import 'source-map-support/register';
 
-export { DepGraphData, DepGraph, PkgManager } from './core/types';
+export {
+  DepGraph,
+  DepGraphData,
+  Pkg,
+  PkgInfo,
+  PkgManager,
+} from './core/types';
 export { createFromJSON } from './core/create-from-json';
 export { DepGraphBuilder } from './core/builder';