chore(deps): update actions/cache action to v4 (#197)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/cache](https://github.com/actions/cache) | action | major |
`v3` -> `v4` |

---

### Release Notes

<details>
<summary>actions/cache (actions/cache)</summary>

### [`v4`](https://github.com/actions/cache/compare/v3...v4)

[Compare Source](https://github.com/actions/cache/compare/v3...v4)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR has been generated by [Renovate
Bot](https://github.com/renovatebot/renovate).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy42NC4yIiwidXBkYXRlZEluVmVyIjoiMzcuNjQuMiIsInRhcmdldEJyYW5jaCI6Im1haW4ifQ==-->

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

.github/workflows/ci.yaml

@@ -40,7 +40,7 @@ jobs:
           echo "::set-output name=dir::$(pip cache dir)"
 
       - name: Cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ steps.pip-cache.outputs.dir }}
           key: ${{ matrix.python-version }}-v1-${{ hashFiles('**/poetry.lock') }}