Bump DeterminateSystems/nix-installer-action from 17 to 18

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 17 to 18.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@21a5447...c723f3a)

---
updated-dependencies:
- dependency-name: DeterminateSystems/nix-installer-action
  dependency-version: '18'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

action.yml

@@ -144,7 +144,7 @@ runs:
 
     - name: Install nix
       if: inputs.skip-nix-installation == 'false'
-      uses: DeterminateSystems/nix-installer-action@21a544727d0c62386e78b4befe52d19ad12692e3  # v17
+      uses: DeterminateSystems/nix-installer-action@c723f3a885e3f1d866d91f4f0c33dd44b1fc7c60  # v18
       with:
         logger: pretty
         extra-conf: experimental-features = ca-derivations fetch-closure