How to build older releases

[laeubi]

I'm currently try to build an older release (because of #21676) i tried to download the zip from here https://github.com/mono/mono/tags extracted it and run the usual

./autogen.sh --prefix=$PREFIX
make
make install

but it fails with

CMake Error at CMakeLists.txt:48 (add_subdirectory):
  The source directory

    /<some path>/mono-mono-5.20.1.34/external/boringssl

  does not contain a CMakeLists.txt file.

so what is the recommended approach to build older releases?