Bump actions/checkout from 2 to 3 (#6111)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/merge.yaml

@@ -19,9 +19,9 @@ jobs:
       GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
       DISTRIBUTION_UPDATER_TOKEN: "${{ secrets.DISTRIBUTION_UPDATER_TOKEN }}"
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       if: github.event_name == 'push'
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       if: github.event_name == 'workflow_dispatch'
       with:
         fetch-depth: 0
@@ -30,7 +30,7 @@ jobs:
       id: release
       run: echo ::set-output name=branch::v1.0.2
     - name: Checkout release branch
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       with:
         ref: ${{ steps.release.outputs.branch }}
         path: './release'

.github/workflows/sheldon.yaml

@@ -15,17 +15,17 @@ jobs:
     # labels to a PR
     # https://securitylab.github.com/research/github-actions-preventing-pwn-requests
     - name: Checkout repo for OWNER TEST
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       if: contains(github.event.pull_request.labels.*.name, 'safe to test')
       with:
         ref: ${{ github.event.pull_request.head.ref }}
 
     # otherwise, checkout the current master, and the pr to the subdirectory 'pull-request'
     - name: Checkout base repo for pull-request test
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       if: "! contains(github.event.pull_request.labels.*.name, 'safe to test')"
     - name: Checkout pull-request
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       if: "! contains(github.event.pull_request.labels.*.name, 'safe to test')"
       with:
         repository: ${{ github.event.pull_request.head.repo.full_name }}