peerDependencies update to support NextJS 15

[Starkpt]

React 19 Support Request

Currently, react-digraph specifies a peer dependency on react-dom@^18.2.0. This causes conflicts in projects using the latest React 19 release candidates (19.0.0-rc) such as NextJS 15.

Update peerDependencies to include React 19:

"peerDependencies": {
  "react": "^16.8 || ^17.0 || ^18.0 || ^19.0",
  "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0"
}