build(deps): bump cachix/install-nix-action from 25 to 26

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 25 to 26.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@v25...v26)

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

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

Author: dependabot[bot]

.github/workflows/deadnix.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v25
+      - uses: cachix/install-nix-action@v26
       - uses: cachix/cachix-action@v14
         with:
           name: deadnix

.github/workflows/doc.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v25
+      - uses: cachix/install-nix-action@v26
       - name: Build
         run: nix build .#doc
       - name: Deploy

.github/workflows/prebuilt-23.05.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v25
+    - uses: cachix/install-nix-action@v26
     - uses: cachix/cachix-action@v14
       with:
         name: microvm

.github/workflows/prebuilt-23.11.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v25
+    - uses: cachix/install-nix-action@v26
     - uses: cachix/cachix-action@v14
       with:
         name: microvm

.github/workflows/prebuilt-unstable.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v25
+    - uses: cachix/install-nix-action@v26
     - uses: cachix/cachix-action@v14
       with:
         name: microvm

.github/workflows/prebuilt.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v25
+    - uses: cachix/install-nix-action@v26
     - uses: cachix/cachix-action@v14
       with:
         name: microvm