Bump DeterminateSystems/nix-installer-action

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


Updates `DeterminateSystems/nix-installer-action` from 14 to 15
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@da36cb6...b92f665)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci-nix.yml

@@ -29,7 +29,7 @@ jobs:
     timeout-minutes: 30
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@da36cb69b1c3247ad7a1f931ebfd954a1105ef14 # v14
+      - uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
       - uses: DeterminateSystems/magic-nix-cache-action@87b14cf437d03d37989d87f0fa5ce4f5dc1a330b # v8
       - run: nix flake check
       - run: nix develop --command echo 'This step should be done before any other "nix develop" steps because of measuring Nix build time'

.github/workflows/reusable-bump-flake-lock-and-selfup.yml

@@ -76,7 +76,7 @@ jobs:
           # Needed to specify token for checkout phase, only in pushing phase is too late
           # https://github.com/orgs/community/discussions/27072#discussioncomment-3254515
           token: ${{ steps.publish-token.outputs.token }}
-      - uses: DeterminateSystems/nix-installer-action@da36cb69b1c3247ad7a1f931ebfd954a1105ef14 # v14
+      - uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
       - uses: DeterminateSystems/magic-nix-cache-action@87b14cf437d03d37989d87f0fa5ce4f5dc1a330b # v8
       - name: Fetch active PRs by me
         id: fetch-active-prs