GHA: add aarch64 qemu vm for nix

Author: itslychee

.github/workflows/build.yml

@@ -1,3 +1,4 @@
+---
 name: "Build Packages"
 on:
   pull_request:
@@ -23,9 +24,15 @@ jobs:
     if: needs.pre-job.outputs.should_skip != 'true'
     steps:
       - uses: actions/checkout@v4
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
       - uses: cachix/install-nix-action@v31
         with:
           nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: |
+            extra-platforms = aarch64-linux i686-linux
       - uses: cachix/cachix-action@v16
         with:
           name: wires

.github/workflows/pr-preview.yml

@@ -1,3 +1,4 @@
+---
 name: "PR Preview"
 on:
   push:
@@ -35,9 +36,15 @@ jobs:
       - uses: actions/checkout@v4
         with:
           ref: ${{ needs.base-ref.outputs.base-ref }}
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
       - uses: cachix/install-nix-action@v31
         with:
           nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: |
+            extra-platforms = aarch64-linux i686-linux
       - uses: cachix/cachix-action@v16
         with:
           name: wires
@@ -74,9 +81,15 @@ jobs:
     if: needs.eval-head.outputs.drv != needs.eval-base.outputs.drv
     steps:
       - uses: actions/checkout@v4
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
       - uses: cachix/install-nix-action@v31
         with:
           nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: |
+            extra-platforms = aarch64-linux i686-linux
       - uses: cachix/cachix-action@v16
         with:
           name: wires