Add Python 3.13 to CI

[dwskoog]

• add conda environment file for 3.13
• add py313 to test.strategy.matrix

I noticed that there are several DeprecationWarnings around event loop uses. I can include changes for resolving those as well. It seems like they might be real problems in the 3.14+ world as there are major changes around asyncio there:

• 3.14 turns off the creation an event loop in get_event_loop and strongly encourages just using get_running_loop
• 3.14 deprecates event loop policies entirely which are scheduled for removal in 3.16
• Tornado 6.5 IOLoop is basically just a wrapper for asyncio according to their docs and 6.2+ changes several behaviors of the IOLoop

Most of the changes were just in the test cases, but the API change in Tornado impacts streamz/core.py as that is eagerly trying to create an event loop in an incorrect place.

[amotl]

3.14 deprecates event loop policies entirely which are scheduled for removal in 3.16

This patch might already include relevant adjustments?

• Add support for Python 3.14 #483

[dwskoog]

3.14 deprecates event loop policies entirely which are scheduled for removal in 3.16

This patch might already include relevant adjustments?

• Add support for Python 3.14 #483

The child watcher issue that you ran into is a good example. Those were deprecated in 3.12 and replaced with OS-specific "optimal" implementations and the ability to control a watcher was deprecated in favor of baking that in to the loop factory itself. More than that however, the behavior of get_event_loop changed as well. In 3.12 they deprecated the "create new loop if none" behavior and in 3.14 they made it an error. I crawled through the 3.12 and 3.13 builds to find the deprecation warnings and reconciled the Python 3.12+ changes with Tornado 6.2+ changes. I have a couple commits on another branch that resolves those. One of them looks like it is a real change that the main code base needs.

[martindurant]

Pushing this is, it's a good step that can't hurt anything.