chore: bump up actions/cache action to v4 (#16)

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This PR contains the following updates:

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

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### Release Notes

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

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

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

</details>

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.github/workflows/CI.yml

@@ -97,7 +97,7 @@ jobs:
           toolchain: stable
           targets: ${{ matrix.settings.target }}
       - name: Cache cargo
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             ~/.cargo/registry/index/