build(deps): bump DeterminateSystems/update-flake-lock from 20 to 28

Bumps [DeterminateSystems/update-flake-lock](https://github.com/determinatesystems/update-flake-lock) from 20 to 28.
- [Release notes](https://github.com/determinatesystems/update-flake-lock/releases)
- [Commits](DeterminateSystems/update-flake-lock@v20...v28)

---
updated-dependencies:
- dependency-name: DeterminateSystems/update-flake-lock
  dependency-version: '28'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/update-flake-lock.yml

@@ -12,7 +12,7 @@ jobs:
         uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v9
       - name: Update flake.lock
-        uses: DeterminateSystems/update-flake-lock@v20
+        uses: DeterminateSystems/update-flake-lock@v28
         with:
           token: ${{ secrets.GH_TOKEN_FOR_UPDATES }}
           pr-title: "chore(deps): update flake.lock"