Build Docker images with GitHub Actions (#16)

* WIP GitHub Actions Workflow

* Split into reusable workflow

* Generate MXE and Win builds

.github/workflows/build.yaml

@@ -0,0 +1,63 @@
+name: Build
+
+on:
+  workflow_call:
+    inputs:
+      file:
+        required: true
+        type: string
+        description: Dockerfile to use
+      tag:
+        required: true
+        type: string
+        description: Docker tag to generate
+      load:
+        required: false
+        type: boolean
+        default: false
+        description: Load docker image
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE: ${{ github.repository_owner }}/qt
+
+jobs:
+  build:
+    name: build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Login to GHCR
+      uses: docker/login-action@v2
+      with:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+        registry: ${{ env.REGISTRY }}
+
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v2
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v2
+
+    - name: Docker meta
+      id: meta
+      uses: docker/metadata-action@v4
+      with:
+        images: ${{ env.REGISTRY }}/${{ env.IMAGE }}
+        flavor: |
+          latest=false
+        tags: |
+          type=raw,value=${{ inputs.tag }}
+          type=ref,event=tag,enable=${{ inputs.tag == 'latest' }}
+
+    - name: Build
+      uses: docker/build-push-action@v4
+      with:
+        file: ${{ inputs.file }}
+        sbom: true
+        provenance: true
+        load: ${{ inputs.load || 'false' }}
+        push: ${{ github.event_name != 'pull_request' }}
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}