Fix package.json
Fix package.json

* Add `repository` (fixes `npm repo rebound`)
* Add `bugs` (fixes `npm bugs rebound`)
* Add `keywords` (helps discoverability with `npm search`)
* Add `author`
* Add `license`

szpnygo/rebound,ISkyLove/rebound,vamsirajendra/rebound,RahulSDeshpande/rebound,wangziqiang/rebound,pranavlathigara/rebound,gk23/rebound,wangkang0627/rebound,hejunbinlan/rebound,fanzlei/rebound,PsyGik/rebound,zzuli4519/rebound,ruisebastiao/rebound,ppamorim/rebound,knappador/rebound,LeonCooper/rebound,JackLeeMing/rebound,Ricordo/rebound,xiaopengs/rebound,omegasoft7/rebound,siddhartharay007/rebound,gowthamlakshman/rebound,shijian95/rebound,hgl888/rebound,sathiamour/rebound,Casper3635/rebound