Problem: Current requirement is Git>=2.36 as `--also-filter-submodules`
flag for `git clone` was introduced there. This is problematic since
default Git version on Ubuntu 22.04 is 2.34.
Solution: Relax minimal Git version to be (at least) 2.0 by selectively
applying necessary flags based on the current Git version.
As 2.0.0 was released in 2014-05-28 (almost the same age as Neovim
project itself), it is reasonable to drop any mention and checks on
minimal version altogether.
e4e6605943
