build(deps): bump actions/checkout from 6 to 7

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>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -29,7 +29,7 @@ jobs:
   formatting:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Install dependencies
       run: |
         npm install prettier prettier-plugin-sh --save-dev
@@ -64,7 +64,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     container: ${{ matrix.container }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Install dependencies
         if: ${{ matrix.install != '' }}
         run: ${{ matrix.install }}
@@ -89,7 +89,7 @@ jobs:
     name: 'macOS (brew)'
     runs-on: macOS-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Install basicswap-bash
       run: |
         ./basicswap-install.sh --new --tor --fullnode --internal --regtest