Switch codecov secret

[waynexia]

This project used to use codecov to collect and show unit test coverage.

https://github.com/datafusion-contrib/datafusion-orc/blob/40b2a3ec2bbb867ffbd6b7e800db7ac14839ddfe/.github/workflows/ci.yml#L129-L136

To make it work in this repository, we need to switch repo in codecov as well. The codecov app is installed to this repo, but I can't generate a secret in codecov. Maybe this is because of some message delay, I'd check again tomorrow.

[waynexia]

I've set the token from the previous repo into this one.