Day.js 1.11.1 发布

Bug Fixes

• add Bengali (Bangladesh) [bn-bd] locale (#1806) (840ed76)
• refactor replace deprecated String.prototype.substr() (#1836) (627fa39)
• Update German [de] locale, adds the abbreviations for month including a . in the end, as in September -> Sept. (#1831) (4e2802c)
• update Italian (Switzerland) [it-ch] locale relativeTime (#1829) (8e6d11d)
• update Kurdish [ku] locale strings and formatted output contains non-standard kurdish characters (#1848) (a597d0b)
• update locale bo [Tibetan]: corrected the orders in formats (#1823) (e790516)