fix: handle release objects with 'invalid' names

[JacobCoffee]

Description

• Fixes issue with /downloads/windows when trying to parse a non-standard relase object version

[zooba]

The root cause that got us here was that I ticked "show on download page" for a PyManager release, which I shouldn't have done. https://github.com/python/pythondotorg/blob/main/downloads/managers.py#L16 would have filtered it out and we never would've hit this path.

[zooba]

Not disagreeing with making the function not crash, to be clear. Maybe it's just as good to make get_version return an empty string in the "not a real version" case?

[JacobCoffee]

whichever you prefer, or if it's just better to document/know that show on download page shouldn't be enabled for pymanager releases? you all are the release experts :D

[zooba]

if it's just better to document/know ...

It never is! 😆

Let's at least make sure that checking the box doesn't bring down the site, and that unchecking it (which I have already done) fixes up any weird display on the page. Then we can rely on documentation from there, I think.

[JacobCoffee]

@zooba does f809fd1 work for you? or did i misunderstand

➜ docker compose run --rm web ./manage.py test downloads
[+] Creating 2/2
 ✔ Container pythondotorg-redis-1     Running              0.0s 
 ✔ Container pythondotorg-postgres-1  Running              0.0s 

System check identified 2 issues (0 silenced).
.................................................................
----------------------------------------------------------------------
Ran 65 tests in 10.299s

OK
Destroying test database for alias 'default'...

[zooba]

Yeah, that's the other approach I was thinking of. Both are fine, but I think the latter is a bit cleaner/safer over time.