Exclude from objectron/proto/objectron/proto.py from `just py-forma…

…t` (#2562)

### What

For some reason, `objectron/proto/objectron/proto.py` relies on
old-style annotation, so it broke with #2361 and was subsequently fixed
by #2559. `just py-format` insist on reverting that latest fix, so the
file is explicitly excluded from `pyupgrade`. I used a pretty ugly hack
because `pyupgrade` is [way too
opinionated](asottile/pyupgrade#809) to even
accept comment-based disabling.

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested https://demo.rerun.io/pr/2562 (if applicable)

<!-- This line will get updated when the PR build summary job finishes.
-->
PR Build Summary: https://build.rerun.io/pr/2562

<!-- pr-link-docs:start -->
Docs preview: https://rerun.io/preview/4d0b2b4/docs
Examples preview: https://rerun.io/preview/4d0b2b4/examples
<!-- pr-link-docs:end -->

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

justfile

@@ -62,7 +62,9 @@ py-format:
     set -euxo pipefail
     black --config rerun_py/pyproject.toml {{py_folders}}
     blackdoc {{py_folders}}
-    pyupgrade --py38-plus `find {{py_folders}} -name "*.py" -type f`
+    # Note: proto.py relies on old-style annotation to work, and pyupgrade is too opinionated to be disabled from comments
+    # See https://github.com/rerun-io/rerun/pull/2559 for details
+    pyupgrade --py38-plus `find {{py_folders}} -name "*.py" -type f ! -path "examples/python/objectron/proto/objectron/proto.py"`
     ruff --fix --config rerun_py/pyproject.toml  {{py_folders}}
 
 # Check that all the requirements.txt files for all the examples are correct