chore(repo): update nx agents to use v4 of cache and checkout (#27122)

<!-- Please make sure you have read the submission guidelines before
posting an PR -->
<!--
https://github.com/nrwl/nx/blob/master/CONTRIBUTING.md#-submitting-a-pr
-->

<!-- Please make sure that your commit message follows our format -->
<!-- Example: `fix(nx): must begin with lowercase` -->

<!-- If this is a particularly complex change or feature addition, you
can request a dedicated Nx release for this pull request branch. Mention
someone from the Nx team or the `@nrwl/nx-pipelines-reviewers` and they
will confirm if the PR warrants its own release for testing purposes,
and generate it for you if appropriate. -->

## Current Behavior
<!-- This is the behavior we have today -->
agents.yaml are currently using a pinned version of v3.6

## Expected Behavior
<!-- This is the behavior we should expect with the changes in this PR
-->
agents.yaml are using v4 of the workflow steps

## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->

Fixes #

.nx/workflows/agents.yaml

@@ -11,9 +11,9 @@ launch-templates:
       NPM_CONFIG_PREFIX: '/home/workflows/.npm-global'
     init-steps:
       - name: Checkout
-        uses: 'nrwl/nx-cloud-workflows/v3.6/workflow-steps/checkout/main.yaml'
+        uses: 'nrwl/nx-cloud-workflows/v4/workflow-steps/checkout/main.yaml'
       - name: Cache restore
-        uses: 'nrwl/nx-cloud-workflows/v3.6/workflow-steps/cache/main.yaml'
+        uses: 'nrwl/nx-cloud-workflows/v4/workflow-steps/cache/main.yaml'
         env:
           KEY: 'pnpm-lock.yaml'
           PATHS: |