Fix documentation about funders
Fix documentation about funders

The open technology funding did not actually come from GFOSS, but from
GRNET.

openmeteo/enhydris,openmeteo/enhydris,ellak-monades-aristeias/enhydris,ellak-monades-aristeias/enhydris,kickapoo/enhydris,aptiko/enhydris,aptiko/enhydris,kickapoo/enhydris,kickapoo/enhydris,openmeteo/enhydris,aptiko/enhydris,ellak-monades-aristeias/enhydris