Updated fstab.yaml to redirect checkout routes to a single document

[darlantc]

We want all /checkout/ routes to render into a single document, the same way we did for the /account/ route.

Test URLs:

• Before: https://main--petplace--hlxsites.hlx.page/
• After:
  • https://checkout-redirect-rule--petplace--hlxsites.hlx.live/
  • https://checkout-redirect-rule--petplace--hlxsites.hlx.live/?martech=off

[aem-code-sync[bot]]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed. In case there are problems, just click a checkbox below to rerun the respective action.

• [ ] Re-run PSI checks
• [ ] Re-sync branch

Commits

* [ccd3e77](https://github.com/hlxsites/petplace/commit/ccd3e778c847f8c0a8f55d314ace609ca3e07546) :white_check_mark: (latest) * [f77a550](https://github.com/hlxsites/petplace/commit/f77a5503adeb6ebbc474c8cd9c48731a67ea5d25) :white_check_mark:

[aem-code-sync[bot]]

	Page	Scores	Audits	Google
M	/
D	/
M	/?martech=off
D	/?martech=off