Please update MLT7 to 7.4.0 (needed for Kdenlive CI)

[Julius Künzel]

Hi everybody,

for the upcoming 22.04 release we are going to make Kdenlive depend on MLT 
7.4.0. However as you know our CI also uses FreeBSD and the MLT version in the 
backports used by the CI is still 7.0.1. It would be nice to get the MLT 
update soon to fix the CI. So can you please package 7.4.0 and install the 
update to the CI? We also need the MLT Qt bindings.

Thanks in advance and for your packaging work in general!
Julius