Updated gaia default table to gaiadr2.gaia_source

[jcsegovia]

Updated default gaia table.

[astropy-bot]

Hi there @jcsegovia 👋 - thanks for the pull request! I'm just a friendly 🤖 that checks for issues related to the changelog and making sure that this pull request is milestoned and labeled correctly. This is mainly intended for the maintainers, so if you are not a maintainer you can ignore this, and a maintainer will let you know if any action is required on your part 😃.

I noticed the following issues with this pull request:

• The milestone has not been set (this can only be set by a maintainer)
• Changelog entry not present (or pull request number missing) and neither the Affects-dev nor the no-changelog-entry-needed label are set

Would it be possible to fix these? Thanks!

If there are any issues with this message, please report them here.

[keflavich]

@jcsegovia Can we use #1112 instead? I would like the table to be configurable using astropy configuration items. e.g., in #1112, a user would do:

from astroquery.gaia import Gaia
Gaia.MAIN_GAIA_TABLE = 'gaiadr2.gaia_source'

but they could also edit their ~/.astropy/config/astroquery.cfg file to set their default data source.

[jcsegovia]

Yes, #1112 is fine to me. Thanks!

(No need to integrate this branch)

[bsipocz]

Thanks @jcsegovia!