Bump actions/checkout from 6.0.3 to 7.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 6.0.3 to 7.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@df4cb1c...9c091bb)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 7.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci-pr.yaml

@@ -34,7 +34,7 @@ jobs:
         uses: frequenz-floss/gh-action-setup-git@f9d86a01228ee1cadaac5224d4d7626f1eb23f90 # v1.0.0
 
       - name: Fetch sources
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           submodules: true
 

.github/workflows/ci.yaml

@@ -84,7 +84,7 @@ jobs:
         uses: frequenz-floss/gh-action-setup-git@f9d86a01228ee1cadaac5224d4d7626f1eb23f90 # v1.0.0
 
       - name: Fetch sources
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           submodules: true
 
@@ -183,7 +183,7 @@ jobs:
         uses: frequenz-floss/gh-action-setup-git@f9d86a01228ee1cadaac5224d4d7626f1eb23f90 # v1.0.0
 
       - name: Fetch sources
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           submodules: true
 
@@ -223,7 +223,7 @@ jobs:
         uses: frequenz-floss/gh-action-setup-git@f9d86a01228ee1cadaac5224d4d7626f1eb23f90 # v1.0.0
 
       - name: Fetch sources
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           submodules: true