Fix release script if multiple bug fixes subheadings in changelog

[mvdbeek]

Fixes

Traceback (most recent call last):
  File "/Users/mvandenb/src/galaxy/.venv/bin/galaxy-release-util", line 8, in <module>
    sys.exit(cli())
             ^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/galaxy_release_util/point_release.py", line 638, in create_point_release
    package = read_package(package_path)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/galaxy_release_util/point_release.py", line 159, in read_package
    package.package_history = parse_changelog(package)
                              ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mvandenb/src/galaxy/.venv/lib/python3.11/site-packages/galaxy_release_util/point_release.py", line 203, in parse_changelog
    assert isinstance(section_changelog_item, docutils.nodes.bullet_list)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError

[jdavcs]

@mvdbeek I had that fixed locally and never pushed - sorry about that! :)
My fix was this:

assert isinstance(section_changelog_item, docutils.nodes.bullet_list) or isinstance(section_changelog_item, docutils.nodes.system_message)