v0.2.0 2021-04-19 (Paris)

• Add an encoder of multipart/form-data (@dinosaure, #9)
• Provide multipart_form.lwt which is a specialization of multipart_form with lwt and streams (@Armael, @dinosaure, #10)
• Add convenience functions such as map or flatten (@Armael, #10)
• Add Multipart_form.parse (@Armael, #10)
• Add documentation to help user (@Armael, @dinosaure, #10, #11, #13)
• Update the README.md (@dinosaure, #12)