Bump actions/checkout from 6 to 7 (#778)

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  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>

Author: dependabot[bot]

.github/workflows/bump-staging.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout current repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Get current SHA
         id: get_current_sha

.github/workflows/pathoplexus-repo-branch-updates.yml

@@ -13,7 +13,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout loculus_deployments
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
       - name: Extract SHAs
         id: extract-shas
         run: |

.github/workflows/promote-staging-to-production.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout current repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Get staging SHA
         id: get_staging_sha

.github/workflows/self-approval-check.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Get changed files
         id: changed-files

.github/workflows/set-staging-to-be-same-as-current-production.yaml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout current repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Get production SHA
         id: get_production_sha

.github/workflows/use-prod-sha-for-demo.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Get production SHA
         id: get_production_sha