Also update the comment so that people remember to update the port at
the same time, and clarify that updating `cmake-version.cmake` is not
required if there is no change in cmake that we need in our buildsystem.
For some reason (for me) on Ubuntu 22.04 the standard make generator
fails:
---------------------------------------------
CMake has bootstrapped. Now run gmake.
make: make: Permission denied
make: *** [Makefile:166: all] Error 127
This seems to be because Source/kwsys/CMakeFiles/cmsys.dir/depend is
missing or not generated. Using ninja works fine though, and as it is
already the default for Serenity proper, it seems reasonable to switch
it here too.
Since we upstreamed CMake support for Serenity, we can use the Platform
files from upstream instead of keeping our local copy. While not added
in this commit, we can add patching capabilities for the platform files
similar to what we do for gdb, llvm, gcc, and binutils later.
