Update actions/cache action to v4 (#66)

This PR contains the following updates:

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

---

### Release Notes

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

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

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

</details>

---

### Configuration

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are satisfied.

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rebase/retry checkbox.

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again.

---

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this box

---

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.github/workflows/terraform.yml

@@ -78,7 +78,7 @@ jobs:
           echo "TFLINT_CONFIG_FILE=${{ github.workspace }}/.tflint.hcl" >> "$GITHUB_ENV"
 
       - name: Cache plugin dir
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         if: success() || failure()
         with:
           path: ~/.tflint.d/plugins