Add 2015-2027 Bankgirot holiday definitions
Add 2015-2027 Bankgirot holiday definitions

These are:

- New Year's Day
- Epiphany
- Good Friday
- Easter Sunday
- Easter Monday
- May 1
- Ascension Day
- Pentecost
- National Day
- Midsummer Eve
- Midsummer Day
- All Saints Day
- Christmas Eve
- Christmas Day
- Boxing Day
- New Year's Eve

gocardless/business