Update GitHub actions to v5 (major) (#464)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v4` -> `v5` |
|
[actions/download-artifact](https://redirect.github.com/actions/download-artifact)
| action | major | `v4` -> `v5` |

---

### Release Notes

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

### [`v5`](https://redirect.github.com/actions/checkout/compare/v4...v5)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v4...v5)

</details>

<details>
<summary>actions/download-artifact (actions/download-artifact)</summary>

###
[`v5`](https://redirect.github.com/actions/download-artifact/compare/v4...v5)

[Compare
Source](https://redirect.github.com/actions/download-artifact/compare/v4...v5)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - Between 01:00 AM and 05:59 AM, only on
Tuesday ( * 1-5 * * 2 ) in timezone Etc/UTC, Automerge - At any time (no
schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

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

---

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

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/canonical/mysql-router-k8s-operator).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS42MC40IiwidXBkYXRlZEluVmVyIjoiNDEuNjAuNCIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsibm90IGJ1ZyBvciBlbmhhbmNlbWVudCJdfQ==-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/check_libs.yaml

@@ -23,7 +23,7 @@ jobs:
     if: ${{ github.event.pull_request.head.repo.full_name == 'canonical/mysql-router-k8s-operator' }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
       - name: Check libs

.github/workflows/ci.yaml

@@ -29,7 +29,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Install tox & poetry
         run: |
           pipx install tox
@@ -43,7 +43,7 @@ jobs:
     timeout-minutes: 20
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Install tox & poetry
         run: |
           pipx install tox

.github/workflows/integration_test.yaml

@@ -16,7 +16,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Set up environment
         run: |
           sudo snap install charmcraft --classic
@@ -97,7 +97,7 @@ jobs:
           df --human-readable
       - name: Checkout
         timeout-minutes: 3
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Set up environment
         timeout-minutes: 5
         run: sudo snap install charmcraft --classic
@@ -108,7 +108,7 @@ jobs:
           go install github.com/snapcore/spread/cmd/spread@latest
       - name: Download packed charm(s)
         timeout-minutes: 5
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           pattern: ${{ inputs.artifact-prefix }}-*
           merge-multiple: true
@@ -199,19 +199,19 @@ jobs:
       # git push origin gh-pages-beta
       # )
       - name: Checkout GitHub pages branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           ref: gh-pages-beta
           path: repo/
       - name: Download default test results
         # Default test results in case the integration tests time out or runner set up fails
         # (So that Allure report will show "unknown"/"failed" test result, instead of omitting the test)
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           path: allure-default-results/
           name: allure-default-results-integration-test
       - name: Download test results
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           path: allure-results/
           pattern: allure-results-integration-test-*

.github/workflows/tiobe_scan.yaml

@@ -18,7 +18,7 @@ jobs:
     timeout-minutes: 60
     steps:
       - name: Checkout the project
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Install system dependencies
         run: sudo apt-get update && sudo apt-get install -y python3-venv