docs: Update resource_management.md

[petrkohut]

Fixed example code snippet for setting up resources for dex.

What type of PR is this?

/kind documentation

What does this PR do / why we need it:
Fixes a bug in documentation for how to configure resources block for Dex ArgoCD component.

Have you updated the necessary documentation?

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

Which issue(s) this PR fixes:
None. This is such a small fix, that I create a PR directly.

How to test changes / Special notes to the reviewer:
The change can be tested by provisioning a new ArgoCD resource and checking that dex got correct resources assigned.

apiVersion: argoproj.io/v1beta1
kind: ArgoCD
metadata:
  name: example-argocd
spec:
  sso:
    dex:
      openShiftOAuth: true
      resources:
        requests:
          cpu: 250m
          memory: 128Mi
        limits:
          cpu: 500m
          memory: 256Mi
    provider: dex
  tls:
    ca: {}

[svghadi]

Thanks @petrkohut for the PR. The change looks good. Can you fix the DOC check by signing the commit?

[petrkohut]

Hey @svghadi ,
it's fixed now. Thanks!

[svghadi]

Awesome 🎉 . Thanks for the contribution @petrkohut .