there is wrong to process output from new version of cmake --help

[xie-jirong]

with new version cmake such as 3.16, the output of cmake --help is different to that of the old version.
And consequently, the function cmake-project--available-generators in cmake-project.el could not
match the output to the regex.

There are two spots needed to modify. First, the character line to start generator.
Secondly, there is some generator occupying two line, and therefore need add \n? just after the name of make tool.

Thanks a lot for your works, and happy new year!

$ diff cmake-project.el~ cmake-project.el
183c183
<                  "The following generators are available on this platform:\n"
---
>                  "The following generators are available on this platform.*\n" ;; for version with "... platform (* marks default):"
189c189
<               "\\s-+\\([^=\n]+?\\)\\s-*=[^\n]+?\n\\([^\\']*\\)\\'" gens-chunk)
---
>               "\\s-+\\([^=\n]+?\\)\n?\\s-*=[^\n]+?\n\\([^\\']*\\)\\'" gens-chunk)