Too many levels of symbolic links #31

Hi, thanks for the great library.

When the folder tree contains a symlink loop, dirhash recurses indefinitely and raises: OSError: [Errno 62] Too many levels of symbolic links: '<…>/test/fixtures/e/symlink'

This is the function call I am using:

    dirhash_result = dirhash(
        folder_path,
        "sha256",
        match=["*"],
        ignore=default_excludes,
        linked_dirs=False,
        linked_files=False,
        allow_cyclic_links=True,
    )

Steps to Reproduce
Point to a directory that includes a symlink cycle. For example: (attaching here for reproducibility - tar-fs_2.1.1-sp1_CVE-2024-12905.zip)

    tar-fs_2.1.1-sp1_CVE-2024-12905/
      source/
        test/
          fixtures/
            e/
              symlink/  →  ../../../../../…   (cycle)

Expected Behavior
should handle symlink loops gracefully—by skipping symlinks entirely based on the parameters of the function call.

Stack trace
File ".../create_dataset_from_metadata.py", line 73, in _deduplicate_folders
folder_hash = compute_sha256_of_folder(folder_path)
File ".../utils.py", line 34, in compute_sha256_of_folder
dirhash_result = dirhash(
File ".../.venv/lib/python3.12/site-packages/dirhash/init.py", line 153, in dirhash
return dirhash_impl(...)
File ".../scantree/_scan.py", line 303, in _scantree_recursive
dir_node = _scantree_recursive(subpath, **fwd_kwargs)
File ".../scantree/_filter.py", line 44, in include
if recursion_path.is_dir() and not self.linked_dirs:
File ".../scantree/_path.py", line 81, in is_dir
return self._dir_entry.is_dir(follow_symlinks=follow_symlinks)
OSError: [Errno 62] Too many levels of symbolic links: '…/test/fixtures/e/symlink'

Would appreciate guidance on how to fix, thanks!