Make CodeCov project changes informational

[omus]

I don't think we should see failed PR status checks when code coverage decreases. We still get good visibility into lines where coverage is missed as those still show up as annotations when viewing the diff

[omus]

Updated this org setting to allow tokenless upload (tokens can still be used): https://app.codecov.io/account/gh/JuliaTime/org-upload-token

[omus]

It appears that this documentation isn't quite right as a .yaml extension does work:

Can I name the file .codecov.yml?

Yes, you can name the file codecov.yml or .codecov.yml. However, the file must still be located in the repository root, dev/, or .github/ directories
– https://docs.codecov.com/docs/codecov-yaml#can-i-name-the-file-codecovyml

[omus]

I've made a suggestion to the codecov documentation. https://docs.codecov.com/suggested-edits/679d44e8944eed0059ea758e

Preview:

Can I rename the .codecov.yml file?

Yes. Alternative file names for codecov.yml include .codecov.yml, codecov.yaml, and .codecov.yaml. However, the file must still be located in the repository root, dev/, or .github/ directories.

[omus]

I've confirmed that both .codecov.yaml and codecov.yaml are supported.

[omus]

I've deleted the secret from the repository