Release workflow updates

[jonathansick]

• [x] Check the box to confirm that you are familiar with the contributing guidelines and/or indicate (check the box) that you are familiar with our contributing workflow.
• [x] Confirm that any contributed tutorials contain a complete Introduction which includes an Author list, Learning Goals, Keywords, Companion Content (if applicable), and a Summary.
• [x] Check the box to confirm that you are familiar with the Astropy community code of conduct and you agree to follow the CoC.

This PR makes two changes to the build.yml workflow for making tutorials releases:

1. Switch to make executeall and make convertall for consistency with the PR-testing workflow. Note this does drop the exclusion of conesearch — is this ok?
2. Only run the dispatch to astropy/learn-astropy when running from the origin repo. This prevents errors when running from forked repos that both shouldn't be dispatching to astropy/astropy-learn and don't have the GitHub secret set.

[adrn]

Failing build seems to be related to pyvo, which recently released a new version? Any ideas @pllim?

[pllim]

Error retrieving astropy-helpers from PyPI -- Has it ever worked before? Maybe you want to wait for astropy/pyvo#290

[pllim]

p.s. astropy-helpers is a Git submodule and should not be installed like a package. And we no longer really support it.

[adrn]

@pllim We aren't explicitly installing astropy-helpers: it looks like it is getting installed by pyvo from just doing pip install pyvo. See: https://github.com/astropy/astropy-tutorials/runs/5143293078?check_suite_focus=true That seems like an issue?

[pllim]

If it is from pyvo, might as well wait for astropy/pyvo#290 .

[adrn]

FYI @pllim: Pinning to pyvo=v1.2.0 fixed this issue, so it seems to be a v1.2.1 issue (released ~2 weeks ago?).

[pllim]

Well, @tomdonaldson is in the midst of releasing another version of pyvo, so you should open a follow-up issue to unpin when that happens.