Add locale for en-SG

[FarsanRashid]

Basic information

• What is the language code according to ISO 639-1?
  en

• What is the country code according to ISO 3166-2?
  SG

• Provide a list of all holidays, i.e. days "which are defined by law on which business or work are suspended or reduced"

1. New Year's Day, Monday, 2 January 2023
2. Chinese New Year, Monday, 23 January 2023
3. Chinese New Year, Tuesday, 24 January 2023
4. Good Friday, Friday, 7 April 2023
5. Hari Raya Puasa, Saturday, 22 April 2023
6. Labour Day, Monday , 1 May 2023
7. Vesak Day, Friday, 2 June 2023
8. Hari Raya Haji, Thursday, 29 June 2023
9. National Day, Wednesday, 9 August 2023
10. Deepavali, Monday, 13 November 2023
11. Christmas Day, Monday, 25 December 2023

• Are holidays moved to a different date, e.g. if they fall on a saturday/sunday/...? If yes, which holidays and what is the algorithm?
  In lieu leave for Hari Raya Puasa, Saturday, 22 April 2023 can be taken on Saturday, 24 April 2023

• Are holidays observed on a different date (is there a substitute holiday), e.g. if they fall on a saturday/sunday/...? If yes, which holidays and what is the algorithm?
  Already adjusted in list of holidays section

• If possible, provide the legal sources which define the holidays.

1. https://www.mom.gov.sg/employment-practices/public-holidays
2. https://www.mom.gov.sg/employment-practices/public-holidays-entitlement-and-pay

• Is it a regional or nation-wide holiday?
  All holidays are nation-wide

• If fixed, provide the date in format MM-DD

1. New Year's Day, Monday, 01-02
2. Chinese New Year, Monday, 01-23
3. Chinese New Year, Tuesday, 01-24
4. Good Friday, Friday, 04-07
5. Hari Raya Puasa, Saturday, 04-22 (In lieu leave on Monday 04-24)
6. Labour Day, Monday , 05-01
7. Vesak Day, Friday, 06-02
8. Hari Raya Haji, Thursday, 06-29
9. National Day, Wednesday, 08-09
10. Deepavali, Monday, 11-13
11. Christmas Day, Monday, 12-25

• If the holiday is proclaimed by the government: Can you provide the source?

1. https://www.mom.gov.sg/employment-practices/public-holidays
2. https://www.mom.gov.sg/employment-practices/public-holidays-entitlement-and-pay

[nathanielmiller23]

Opened a PR to solve this issue: #108