Update argocd.md

[ThomVivet]

Fix small typo

What type of PR is this? /kind documentation

What does this PR do / why we need it: Fix small typo into documentation

Have you updated the necessary documentation?

• [ ] Documentation update is required by this PR.
• [ ] Documentation has been updated.

Which issue(s) this PR fixes:

Fixes #?

How to test changes / Special notes to the reviewer:

[reginapizza]

hi @ThomVivet, sorry for the delay here. If you want us to approve this PR you need to sign off on the DCO in order for all checks to pass. Please see https://github.com/argoproj-labs/argocd-operator/pull/878/checks?check_run_id=12172639457 for how to do that via a rebase with signoff. Thanks!