github: bump the github-dependencies group with 1 update

Bumps the github-dependencies group with 1 update: [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action).

- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](bc7b192574...5620eb4af6)

---
updated-dependencies:
- dependency-name: DeterminateSystems/nix-installer-action
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-dependencies
...

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

.github/workflows/nix-linux.yml

@@ -17,6 +17,6 @@ jobs:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
-      - uses: DeterminateSystems/nix-installer-action@bc7b19257469c8029b46f45ac99ecc11156c8b2d
+      - uses: DeterminateSystems/nix-installer-action@5620eb4af6b562c53e4d4628c0b6e4f9d9ae8612
       - uses: DeterminateSystems/magic-nix-cache-action@a04e6275a6bea232cd04fc6f3cbf20d4cb02a3e1
       - run: nix build --print-build-logs --show-trace

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

@@ -11,7 +11,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@bc7b19257469c8029b46f45ac99ecc11156c8b2d
+        uses: DeterminateSystems/nix-installer-action@5620eb4af6b562c53e4d4628c0b6e4f9d9ae8612
       - name: Update flake.lock
         uses: DeterminateSystems/update-flake-lock@da2fd6f2563fe3e4f2af8be73b864088564e263d
         with: