calcurse-caldav: Encode the request body in UTF-8
calcurse-caldav: Encode the request body in UTF-8

When a string is passed to HTTPConnection.request(), it is automatically
ISO 8859-1 encoded. Therefore, since we already specify UTF-8 as
character set in the headers, we need to UTF-8 encode the request body
manually.

Signed-off-by: Lukas Fleischer <c9ca73f8336dcfb037ec2c2abf52d80a6847a5cd@calcurse.org>

lfos/calcurse,lfos/calcurse,lfos/calcurse