ci(actions): bump cachix/cachix-action from 15 to 17

Bumps [cachix/cachix-action](https://github.com/cachix/cachix-action) from 15 to 17.
- [Release notes](https://github.com/cachix/cachix-action/releases)
- [Changelog](https://github.com/cachix/cachix-action/blob/master/RELEASE.md)
- [Commits](cachix/cachix-action@v15...v17)

---
updated-dependencies:
- dependency-name: cachix/cachix-action
  dependency-version: '17'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/nix.yml

@@ -32,7 +32,7 @@ jobs:
       # silently skip). Guard it to the canonical repo so forks don't even
       # attempt the upload. The cache name is optional; remove this step if
       # no cachix cache is ever configured.
-      - uses: cachix/cachix-action@v15
+      - uses: cachix/cachix-action@v17
         if: github.repository == 'LarsArtmann/segment-buffer'
         with:
           name: larsartmann-segment-buffer
@@ -49,7 +49,7 @@ jobs:
       - uses: cachix/install-nix-action@v27
         with:
           nix_path: nixpkgs=channel:nixos-unstable
-      - uses: cachix/cachix-action@v15
+      - uses: cachix/cachix-action@v17
         if: github.repository == 'LarsArtmann/segment-buffer'
         with:
           name: larsartmann-segment-buffer