Add EF Core and Dapper Plus sponsors

Author: khellang

README.md

@@ -102,3 +102,11 @@ Results in the following SQL:
 ```sql
 SELECT strftime('%Y-%m-%d %H:%M:%f', "n"."LocalDateTime", '+2 months', '+2 days', '+2 hours', '+2 seconds')
 ```
+
+## Sponsors
+
+[Entity Framework Extensions](https://entityframework-extensions.net/?utm_source=khellang&utm_medium=EFCore.Sqlite.NodaTime) and [Dapper Plus](https://dapper-plus.net/?utm_source=khellang&utm_medium=EFCore.Sqlite.NodaTime) are major sponsors and proud to contribute to the development of EFCore.Sqlite.NodaTime.
+
+[![Entity Framework Extensions](https://raw.githubusercontent.com/khellang/EFCore.Sqlite.NodaTime/master/entity-framework-extensions-major-sponsor.png)](https://entityframework-extensions.net/bulk-insert?utm_source=khellang&utm_medium=EFCore.Sqlite.NodaTime)
+
+[![Dapper Plus](https://raw.githubusercontent.com/khellang/EFCore.Sqlite.NodaTime/master/dapper-plus-sponsor.png)](https://dapper-plus.net/bulk-insert?utm_source=khellang&utm_medium=EFCore.Sqlite.NodaTime)