Fix a couple of spelling errors (#903)

README.md

@@ -483,7 +483,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Colorado Information Marketplace](https://data.colorado.gov/) | Colorado State Government Open Data | No | Yes | Unknown |
 | [Data USA](https://datausa.io/about/api/) | US Public Data | No | Yes | Unknown |
 | [Data.gov](https://api.data.gov/) | US Government Data | `apiKey` | Yes | Unknown |
-| [Data.parliament.uk](http://www.data.parliament.uk/developers/) | Contains live datasets including information about petitions, bills, MP votes, attendence and more | No | No | Unknown |
+| [Data.parliament.uk](http://www.data.parliament.uk/developers/) | Contains live datasets including information about petitions, bills, MP votes, attendance and more | No | No | Unknown |
 | [District of Columbia Open Data](http://opendata.dc.gov/pages/using-apis) | Contains D.C. government public datasets, including crime, GIS, financial data, and so on | No | Yes | Unknown |
 | [EPA](https://developer.epa.gov/category/apis/) | Web services and data sets from the US Environmental Protection Agency | No | Yes | Unknown |
 | [FEC](https://api.open.fec.gov/developers/) | Information on campaign donations in federal elections | `apiKey` | Yes | Unknown |