Update Copernicus template to 6.0 and sanitize #331

[RLumSK]

Update Copernicus Publications template as discussed previously and, hopefully, sanitize #331 until a new version gets released by Copernicus. I tested the fix on my machine and it works as expected.

• [X] Unless you have done it in any other RStudio's projects before, please sign the individual or corporate contributor agreement for a significant pull request (it is fine not to sign it if a PR is only intended to fix a few typos). You can send the signed copy to jj@rstudio.com.

Note: If I run the checks, some tests throw errors, however, none of them related to the Copernicus template.

[CLAassistant]

All committers have signed the CLA.