Fix dbt docs overview to working url

[remoyson]

This PR fixes the default overview startup page of the docs pointing to an url that is not working anymore.

Checklist

• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have updated the CHANGELOG.md and added information about my change

[emmyoop]

@remoyson thanks for submitting a fix for this and welcome to the community! I know this is a small update but would you mind updating the CHANGELOG.md with your change too? We love giving credit to everyone that helps make dbt what it is today! It looks like there isn't a new section yet for the next version so at the top of the file you would need to add the following:

## dbt-core 1.0.1 (TBD)

### Fixes
- 

Contributors:
- 

I've also submitted a fix via #951 so that older versions of our docs won't have broken links.

[emmyoop]

On more small thing - Since this is a small change to a link it's fine this time but in the future we like to have issues created before PRs.

[remoyson]

@emmyoop Thanks for the feedback! yes happy also to add it to the changelog :)
Maybe stupid question but as you added it in the redirect won't that solve it as well and is this change in url here not really needed anymore as it redirects to a the working url? Or will the docs site also change for version 1.x.x?

[emmyoop]

@remoyson not a stupid question at all! It does indeed fix it but I would really prefer the link be right going forward so we don't have to have redirects everywhere!

[emmyoop]

🎉

[emmyoop]

Thank you for your contribution. Looks great. I'll go ahead and merge it in.