Incompatibility with protobuf-3.20.1

[bojanbg]

Apologies if this is not a pycld3 issue but a cld3 one. I only use it through the Python bindings.

System upgrade switched protobuf to the latest version (3.20.1). After that:

(.venv) [<redacted>]$ python
Python 3.10.4 (main, Mar 23 2022, 23:05:40) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cld3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/<redacted>/.venv/lib/python3.10/site-packages/cld3/__init__.py", line 3, in <module>
    from ._cld3 import *  # noqa
ImportError: libprotobuf.so.30: cannot open shared object file: No such file or directory

Protobuf 3.20.1 publishes libprotobuf.so.31.

Reverting to protobuf 3.19.4 resolves the issue, as that package does have libprotobuf.so.30.