This only adds a test that currently makes sure its not possible
to init a Millisatoshi by a floating number.
Discussion:
As @gallizoltan points out, initialization with a float should be possible:
https://github.com/ElementsProject/lightning/pull/4273#discussion_r540369093
> Millisatoshi(5) / 2 currently works, and removes the half msat.
> So, I think Millisatoshi(5 / 2) should be the same.
This should not affect any consumer of the API since we just shift the actual
implementation from one side to the other, and keep aliases in place so
scripts don't break.
We also bump the version number from 0.0.7.3 to 0.7.4 which allows us to be in
sync with c-lightning itself, and remove the superfluous `0` in front.
Michael Schmoock
Christian Decker