Use arm64 runners for aarch64 builds

As we're now effectively building only aarch64 or amd64, we can simply pass the
arch to the builder image argument.

Author: sairon

.github/workflows/builder.yml

@@ -16,7 +16,7 @@ env:
 jobs:
   init:
     name: Initialize build
-    runs-on: &runs-on-ubuntu ubuntu-24.04
+    runs-on: ubuntu-24.04
     outputs:
       architectures_alpine: ${{ steps.info_alpine.outputs.architectures }}
       architectures_debian: ${{ steps.info_debian.outputs.architectures }}
@@ -61,7 +61,7 @@ jobs:
   build_alpine:
     name: Build ${{ matrix.arch }} alpine ${{ matrix.version }} base image
     needs: init
-    runs-on: *runs-on-ubuntu
+    runs-on: &builder-runs-on ${{ matrix.arch == 'aarch64' && 'ubuntu-24.04-arm' || 'ubuntu-24.04' }}
     permissions: &permissions
       contents: read
       id-token: write
@@ -96,6 +96,7 @@ jobs:
       - name: Build base image
         uses: home-assistant/[email protected]
         with:
+          image: ${{ matrix.arch }}
           args: |
             $BUILD_ARGS \
             --${{ matrix.arch }} \
@@ -107,7 +108,7 @@ jobs:
   build_debian:
     name: Build ${{ matrix.arch }} debian ${{ matrix.version }} base image
     needs: init
-    runs-on: *runs-on-ubuntu
+    runs-on: *builder-runs-on
     permissions: *permissions
     strategy:
       matrix:
@@ -133,6 +134,7 @@ jobs:
       - name: Build base image
         uses: home-assistant/[email protected]
         with:
+          image: ${{ matrix.arch }}
           args: |
             $BUILD_ARGS \
             --${{ matrix.arch }} \
@@ -145,7 +147,7 @@ jobs:
   build_ubuntu:
     name: Build ${{ matrix.arch }} ubuntu ${{ matrix.version }} base image
     needs: init
-    runs-on: *runs-on-ubuntu
+    runs-on: *builder-runs-on
     permissions: *permissions
     strategy:
       matrix:
@@ -182,7 +184,7 @@ jobs:
   build_python:
     name: Build ${{ matrix.arch }} alpine ${{ matrix.version }} - python ${{ matrix.python }} base image
     needs: [init, build_alpine]
-    runs-on: *runs-on-ubuntu
+    runs-on: *builder-runs-on
     permissions: *permissions
     strategy:
       fail-fast: false
@@ -210,6 +212,7 @@ jobs:
       - name: Build base image
         uses: home-assistant/[email protected]
         with:
+          image: ${{ matrix.arch }}
           args: |
             $BUILD_ARGS \
             --${{ matrix.arch }} \