BUG/TST: dt+BDay(n) wrong if n>5, n%5==0 and dt not on offset (GH5890)
DOC: updated release.rst (GH5890)
Merge pull request #5911 from dorandeluz/bday-addition

BUG: dt+BDay(n) wrong if n>5, n%5==0 and dt not on offset (GH5890)