add Singapore's public data (#2265)

README.md

@@ -784,6 +784,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Open Government, Romania](http://data.gov.ro/) | Romania Government Open Data | No | No | Unknown |
 | [Open Government, Russia](https://data.gov.ru/?language=en) | Open Data Portal Russia | `apiKey` | No | Unknown |
 | [Open Government, Saudi Arabia](https://data.gov.sa) | Saudi Arabia Government Open Data | No | Yes | Unknown |
+| [Open Government, Singapore](https://data.gov.sg/) | Singapore Government Open Data | No | Yes | Unknown |
 | [Open Government, Taiwan](https://data.gov.tw/) | Taiwan Government Open Data | No | Yes | Unknown |
 | [Open Government, Thailand](https://data.go.th/) | Thailand Government Open Data | `apiKey` | Yes | Unknown |
 | [Open Government, UK](https://data.gov.uk/) | UK Government Open Data | No | Yes | Unknown |