Determining latest set of TOAs (LATEST_TOA_RELEASE)

[tcromartie]

Currently, the most recent TOA "release" is specified in defaults.yaml. It (par_checker) currently complains that releases in 2025 are "old" just because they don't match the 2021 release specified. We should think about how to change this carefully—presumably because we're doing TOA versioning differently than we did in NG15, this might have broader implications.

[tcromartie]

https://gitlab.nanograv.org/nano-time/ng20/-/issues/16

[rossjjennings]

Updating the "latest" TOA release (as set by the -ver flag in the .tim files) should be as simple as changing a line in the global configuration file. But there may be a bit more to this for a couple of reasons. For one, the -ver flag isn't fully consistent even in the AO/GBT/VLA data in the v1.0 data set, but regenerating the TOAs should fix this. For another, we probably want to keep using a different -ver flag for the CHIME data, since it is processed using a different pipeline (and the flag value contains a git hash of the version of toagen used to produce the data). So we may want to accept two different versions as "latest," one for CHIME and one for everything else, which isn't possible in the current code.

In short, the work needed here on the PINT Pal side is more about allowing more than one version to be accepted as "latest" than changing the specific version that is accepted, since the latter can be done in the data set repo.

[mtlam]

Will be solved by #147 once multiple TOA versions are allowed.