Add pull request template (#6347)
Add pull request template (#6347)

* Added PR checklist example

* Add a basic version of pull request template

jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,xinzweb/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,adam8157/gpdb,50wu/gpdb,ashwinstar/gpdb,xinzweb/gpdb,lisakowen/gpdb,greenplum-db/gpdb,lisakowen/gpdb,50wu/gpdb,lisakowen/gpdb,jmcatamney/gpdb,xinzweb/gpdb,ashwinstar/gpdb,50wu/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,lisakowen/gpdb,adam8157/gpdb,50wu/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,50wu/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,adam8157/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,50wu/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,adam8157/gpdb,greenplum-db/gpdb,lisakowen/gpdb,greenplum-db/gpdb,xinzweb/gpdb,lisakowen/gpdb,adam8157/gpdb