ci: bump actions/cache (#583)

# Motivation

In CIs, we need to bump `actions/cache` to v4, since v2 will be
deprecated soon.

> Annotations
> 1 warning
>
[e2e](https://github.com/dfinity/gix-components/actions/runs/13272676338/job/37055563318)
> Your workflow is using a version of actions/cache that is scheduled
for deprecation, actions/cache@v2. Please update your workflow to use
either v3 or v4 of actions/cache to avoid interruptions. Learn more:
https://github.blog/changelog/2024-12-05-notice-of-upcoming-releases-and-breaking-changes-for-github-actions/#actions-cache-v1-v2-and-actions-toolkit-cache-package-closing-down

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Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

Author: AntonioVentilii

.github/workflows/checks.yml

@@ -120,7 +120,7 @@ jobs:
           echo "google-chrome --version"
           google-chrome --version
       - name: Cache and restore samples
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         id: samples
         with:
           path: ./samples/