Bugfix for a PROJ runtime error

[davemfish]

A user's PROJ_DATA env variable could trigger a RuntimeError if compatible proj.db file is not found at the location given by PROJ_DATA. In order to ensure that invest always looks for proj.db in the frozen pyinstaller environment, we can set PROJ_DATA at runtime.

We were already doing this for PROJ_LIB, but that variable has been replaced by PROJ_DATA: https://proj.org/en/stable/usage/environmentvars.html#envvar-PROJ_DATA

Fixes #1742

Checklist

• Updated HISTORY.rst and link to any relevant issue (if these changes are user-facing)
• Updated the user's guide (if needed)
• Tested the Workbench UI (if relevant)

[davemfish]

I'll keep this in draft until I hear back from the user that encountered this issue. They were sent a dev build. I was also able to reproduce the problem though, so I think this is a good fix.

[davemfish]

I did not hear back from the forum user, but I think we can go forward with this PR anyway.

[claire-simpson]

Thanks @davemfish! Is leaving in the PROJ_LIB to ensure backwards compatibility? And is it ok that the Windows workbench test failed (assume that doesn't have to do with your changes)?

[davemfish]

Thanks @davemfish! Is leaving in the PROJ_LIB to ensure backwards compatibility?

Yes, the docs state that PROJ_LIB is still supported, so if a user has it defined already I think we still want to overwrite it for the invest process. Perhaps PROJ_DATA takes precedence anyway, but seems safe to just keep them both defined.

And is it ok that the Windows workbench test failed (assume that doesn't have to do with your changes)?

Thanks @claire-simpson , I just re-ran that failed test. Hopefully it passes. It does seem to be an unrelated, intermittent failure.