Update cachix/install-nix-action to fix CI

Ref: https://github.com/cachix/install-nix-action/issues/183

.github/workflows/ci.yaml

@@ -12,6 +12,9 @@ on:
     types:
       - completed
 
+permissions:
+  contents: read
+
 jobs:
   # TODO: `nix flake check` costs too much time and memory for GitHub Actions machines.
 
@@ -24,7 +27,7 @@ jobs:
       uses: actions/checkout@v3
 
     - name: Install Nix
-      uses: cachix/install-nix-action@v18
+      uses: cachix/install-nix-action@v22
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
 
@@ -99,7 +102,7 @@ jobs:
       uses: actions/checkout@v3
 
     - name: Install Nix
-      uses: cachix/install-nix-action@v18
+      uses: cachix/install-nix-action@v22
       with:
         nix_path: nixpkgs=channel:${{ matrix.nixpkgs-channel }}
         install_url: ${{ matrix.nix_install_url }}
@@ -147,7 +150,7 @@ jobs:
       uses: actions/checkout@v3
 
     - name: Install Nix
-      uses: cachix/install-nix-action@v18
+      uses: cachix/install-nix-action@v22
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
 

.github/workflows/sync-channels.yaml

@@ -6,6 +6,9 @@ on:
 
   workflow_dispatch:
 
+permissions:
+  contents: write
+
 jobs:
   sync-channels:
     name: Sync channels and prefetch toolchains
@@ -19,7 +22,7 @@ jobs:
         ref: master
 
     - name: Install Nix
-      uses: cachix/install-nix-action@v18
+      uses: cachix/install-nix-action@v22
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
 

.github/workflows/update-stable.yaml

@@ -17,6 +17,9 @@ on:
     types:
       - completed
 
+permissions:
+  contents: write
+
 jobs:
   update-stable:
     name: Update "stable" branch