ci: run nix workflow on all branches

Remove branch restriction from nix workflow to run on all pushes,
not just main branch. This ensures CI validation runs on feature
branches and pull requests.

Author: albertodvp

.github/workflows/nix.yaml

@@ -2,8 +2,6 @@
 name: nix
 on:
   push:
-    branches:
-      - main
   pull_request:
 permissions:
   contents: read
@@ -20,7 +18,7 @@ jobs:
         go-version: ['124', '125']
     steps:
       - name: Checkout
-        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcf5dd907a8 # v5
+        uses: actions/checkout@v5
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -44,7 +42,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout
-        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcf5dd907a8 # v5
+        uses: actions/checkout@v5
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:

flake.nix

@@ -342,6 +342,7 @@
             gofumpt
             jq
             config.treefmt.build.wrapper
+            act
           ];
 
           shellHook = ''