chore: add ISSUE_TEMPLATE.md (#2141)
chore: add ISSUE_TEMPLATE.md (#2141)


c3js/c3,c3js/c3,alanhamlett/c3,masayuki0812/c3,c3js/c3,alanhamlett/c3,Aloomaio/c3,c3js/c3,masayuki0812/c3,Aloomaio/c3,alanhamlett/c3