The project_options should only FetchContents of other repos with stable versions tags

[Claus Klein]

Some of the other CMake git repos used by this project have no stable git tag.

• Would it be possible to change this?
• Would it also possible to document this dependencies too?
• Is it possible to always use FetchContent_MakeAvailable()?
• see ClausKlein#5 (review)

i.e.

  # in PackageProject.cmake
  # download ForwardArguments
  FetchContent_Declare(
    _fargs
    URL https://github.com/polysquare/cmake-forward arguments/archive/8c50d1f956172edb34e95efa52a2d5cb1f686ed2.zip)

# in VCEnvironment.cmake
# Using Windows MSVC toolchain
FetchContent_Declare(
        _msvc_toolchain URL "https://github.com/aminya/Toolchain/archive/95891a1e28a406ffb22e572f3ef24a7a8ad27ec0.zip")

[Claus Klein]

@lefticus @aminya please note this brand new CMake v3.24 option I want to use:

cmake -DCMAKE_PROJECT_TOP_LEVEL_INCLUDES=$PWD/mycomp_provider.cmake -S . -B build -G Ninja -Wno-dev

[Claus Klein]

see too https://discourse.cmake.org/t/fetchcontent-vs-vcpkg-conan/6578

[Amin Yahyaabadi]

Since v0.26.1 all the fetch contents are based on a stable tag