Add Jawnt to the list of cosignatories

https://www.jawntpass.com/blog/jawnt-mobility-data-interoperability-principles

Author: etienne0101

docs/en/cosignatories.md

@@ -32,6 +32,7 @@
 - [Interline](https://interline.io)
 - [Ito World](https://www.itoworld.com/)
 - [Jarvus Innovations](https://jarv.us/)
+- [Jawnt](https://www.jawntpass.com)
 - [King County, Washington](https://kingcounty.gov/)
 - [Kuba](https://www.kubapay.com/)
 - Albert Kochaphum, Individual