Add dev build workflow (#1017)

* Add development build version part to version number

Add third part in the version number to indicate development builds.
Generate a default version number based on the date, e.g.
"5.6.dev20201124".

* Add GitHub Action workflow for development builds

Add another GitHub workflow for development builds. Make it triggered
only for now. The version number is generated by the workflow and
passed to all builds to make sure all builds have the same development
build version.

* Add documentation

.github/workflows/dev.yml

@@ -0,0 +1,80 @@
+# Home Assistant Operating System build workflow
+
+name: Development build
+
+on:
+  workflow_dispatch:
+
+jobs:
+  version:
+
+    name: Generate version
+    runs-on: [ "ubuntu-20.04" ]
+    outputs:
+      version_dev: ${{ steps.version.outputs.version_dev }}
+    steps:
+      - name: Generate Development build version
+        shell: bash
+        id: version
+        run: |
+          version_dev="dev$(date --utc +'%Y%m%d')"
+          echo "Development version \"${version_dev}\""
+          echo "::set-output name=version_dev::${version_dev}"
+
+  build:
+    name: Release build for ${{ matrix.board.name }}
+    needs: version
+    strategy:
+      matrix:
+        board:
+          - {"name": "ova", "output": "ova", "runner": "x86-64-runner"}
+          - {"name": "intel_nuc", "output": "intel-nuc", "runner": "x86-64-runner"}
+          - {"name": "odroid_c2", "output": "odroid-c2", "runner": "aarch64-runner"}
+          - {"name": "odroid_c4", "output": "odroid-c4", "runner": "aarch64-runner"}
+          - {"name": "odroid_n2", "output": "odroid-n2", "runner": "aarch64-runner"}
+          - {"name": "odroid_xu4", "output": "odroid-xu4" , "runner": "aarch64-runner"}
+          - {"name": "rpi", "output": "rpi", "runner": "arm-runner"}
+          - {"name": "rpi0_w", "output": "rpi0-w", "runner": "arm-runner"}
+          - {"name": "rpi2", "output": "rpi2", "runner": "arm-runner"}
+          - {"name": "rpi3", "output": "rpi3", "runner": "arm-runner"}
+          - {"name": "rpi3_64", "output": "rpi3-64", "runner": "aarch64-runner"}
+          - {"name": "rpi4", "output": "rpi4", "runner": "arm-runner"}
+          - {"name": "rpi4_64", "output": "rpi4-64", "runner": "aarch64-runner"}
+          - {"name": "tinker", "output": "tinker", "runner": "arm-runner"}
+    runs-on: ${{ matrix.board.runner }}
+
+    steps:
+      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+      - uses: actions/checkout@v2
+
+      - name: Build container
+        run: docker build -t haos-builder .
+
+      - name: 'Add release PKI certs'
+        env:
+          RAUC_CERTIFICATE: ${{ secrets.RAUC_CERTIFICATE }}
+          RAUC_PRIVATE_KEY: ${{ secrets.RAUC_PRIVATE_KEY }}
+        run: |
+          echo -e "-----BEGIN CERTIFICATE-----\n${RAUC_CERTIFICATE}\n-----END CERTIFICATE-----" > cert.pem
+          echo -e "-----BEGIN PRIVATE KEY-----\n${RAUC_PRIVATE_KEY}\n-----END PRIVATE KEY-----" > key.pem
+
+      - name: Build
+        run: |
+          BUILDER_UID="$(id -u)"
+          BUILDER_GID="$(id -g)"
+          docker run --rm --privileged -v "${GITHUB_WORKSPACE}:/build" \
+            -e BUILDER_UID="${BUILDER_UID}" -e BUILDER_GID="${BUILDER_GID}" \
+            -v "${{ matrix.board.runner }}-build-cache:/cache" \
+            haos-builder make VERSION_DEV=${{ needs.version.outputs.version_dev }} ${{ matrix.board.name }}
+
+      - name: Upload images
+        uses: appleboy/scp-action@master
+        with:
+          host: ${{ secrets.DEV_HOST }}
+          username: ${{ secrets.DEV_USERNAME }}
+          port: ${{ secrets.DEV_PORT }}
+          key: ${{ secrets.DEV_SCP_KEY }}
+          source: "release/*"
+          target: ${{ secrets.DEV_TARGET_PATH }}
+          strip_components: 1
+