ci: update long and network tests to use python 3.13

[terriko]

Our long tests and network "may fail" tests currently use python 3.10. I'd like to have those all upgraded to use python 3.13 going forwards.

The big reason is that we've been experiencing an out of memory issue #4710 that we believe to be related to the size of data now in OSV. One of the workarounds includes using python 3.13 (which has other memory improvements), so switching all of those jobs to python 3.13 should help us avoid failures as the OSV data size continues to balloon. There's probably some other benefits around performance and future-proofing but not having CI blocks as GSoC folk get going is my biggest motivation, because if CI gets blocked I'm often the only one who can fix things and it can take a while.

This should be just a couple line change in .github/workflows/testing.yml so I'm marking this as a good first issue for someone.

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[Gyan-max]

Hi @terriko
is this issue still open?

[terriko]

@Gyan-max it's got a PR already #4779 so it's "open" in that I haven't merged that yet, but does not need any additional work at this time because there's already a solution in play.