fix(b-calendar): use `Intl.NumberFormat`  for formatting the number in the date buttons (closes #5171) (#5179)
fix(b-calendar): use `Intl.NumberFormat`  for formatting the number in the date buttons (closes #5171) (#5179)

* fix(b-calendar): use Intl.NumberFormat for formatting the date buttons (closes #5171)

* Update calendar.js

Co-authored-by: Jacob Müller <7ae9a40946a993a46e3f1d4a8ac589d2efe9da89@gmail.com>
bootstrap-vue/bootstrap-vue,bootstrap-vue/bootstrap-vue