workflows: build: add build CI workflow

Signed-off-by: James Calligeros <[email protected]>

Author: chadmed

.github/workflows/build.yaml

@@ -0,0 +1,40 @@
+name: build
+
+on:
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+  workflow_call:
+    outputs:
+        installer_ver:
+            description: asahi-installer built version string
+
+jobs:
+  build:
+      runs-on: ubuntu-latest
+
+      steps:
+        - uses: actions/checkout@v5
+          with:
+            fetch-depth: 0
+            fetch-tags: true
+            submodules: recursive
+
+        - name: Install build dependencies
+          run: |
+            sudo apt-get update
+            sudo apt-get install --no-install-recommends -y gcc-aarch64-linux-gnu
+            sudo apt-get install --no-install-recommends -y 7zip jq
+            rustup target install aarch64-unknown-none-softfloat
+
+        - name: Build asahi-installer
+          run: |
+            ./build.sh
+            echo "installer_ver=$(cat releases/latest)" >> $GITHUB_OUTPUT
+
+        - name: Upload artefact
+          uses: actions/upload-artifact@v4
+          with:
+            name: installer-build
+            path: |
+              releases/*