Fix issue with `asset_ids` in `create-catalog`

[hrodmn]

Related Issue(s): Resolves #14

Description: Rather than overwriting asset_ids variable when running the first collection, conditionally loop through asset_ids or utils.fetch_ids(product) to make sure you are not running asset_ids from one product on the other!

PR checklist:

• [x] Code is formatted (run scripts/format).

• [ ] Code lints properly (run scripts/lint).

  • this is failing due to a typing issue in stactools.core, I think?

  $ scripts/lint
  mypy.....................................................................Failed
  - hook id: mypy
  - exit code: 1
  
  tests/test_commands.py:14: error: Class cannot subclass "CliTestCase" (has type "Any")  [misc]
  Found 1 error in 1 file (checked 10 source files)

• [x] Tests pass (run scripts/test).
  • pytest is passing, but not the linter that runs before it
• [ ] Documentation has been updated to reflect changes, if applicable.
• [x] Changes are added to the CHANGELOG.

[hrodmn]

Looks fine to me, the PR just needs to be updated with main to pick up #16, which I can't do b/c I don't have permissions on https://github.com/ncx-co/threedep.

I rebased my branch to get the latest changes, should be good to go now!

In the future, it can be easier if you create a branch on your fork for the PR -- that allows me to make minor fixup changes if needed.

Ah I see. So instead of pushing changes to main on my forked copy, just push changes to a branch and open a PR to the upstream repo?

[gadomski]

Ah I see. So instead of pushing changes to main on my forked copy, just push changes to a branch and open a PR to the upstream repo?

Yup, that makes it easier to (a) open multiple PRs from your fork, if you'd like to, and (b) repo maintainers (e.g. me) to push changed to your branch.