Add Dart Sass support

But note that the Dart Sass Embedded Protocol is still in beta (beta 5), a main release scheduled for Q1 2021.

Fixes #7380
Fixes #8102

.github/workflows/test.yml

@@ -0,0 +1,81 @@
+on: [push, pull_request]
+name: Test
+jobs:
+  test:
+    env:
+      GOPROXY: https://proxy.golang.org
+      GO111MODULE: on
+    strategy:
+      matrix:
+        go-version: [1.14.x, 1.15.x]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@37335c7bb261b353407cff977110895fa0b4f7d8
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Install Ruby
+      uses: actions/setup-ruby@5f29a1cd8dfebf420691c4c9a0e832e2fae5a526
+      with:
+        ruby-version: '2.7'
+    - name: Install Python
+      uses: actions/setup-python@3105fb18c05ddd93efea5f9e0bef7a03a6e9e7df
+      with:
+        python-version: '3.x'
+    - name: Install Mage
+      run: go get github.com/magefile/mage@07afc7d24f4d6d6442305d49552f04fbda5ccb3e
+    - name: Install asciidoctor
+      uses: reitzig/actions-asciidoctor@7570212ae20b63653481675fb1ff62d1073632b0
+    - name: Checkout code
+      uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
+    - name: Install docutils
+      run: |
+        pip install docutils
+        rst2html.py --version
+    - if: matrix.os == 'ubuntu-latest'
+      name: Install pandoc on Linux
+      run: |
+          sudo apt-get update -y
+          sudo apt-get install -y pandoc
+    - if: matrix.os == 'macos-latest'
+      run: |
+        brew install pandoc
+    - if: matrix.os == 'windows-latest'
+      run: |
+        choco install pandoc
+    - run: pandoc -v
+    - if: matrix.os == 'ubuntu-latest'
+      name: Install dart-sass-embedded Linux
+      run: |
+        curl -LJO https://github.com/sass/dart-sass-embedded/releases/download/1.0.0-beta.5/sass_embedded-1.0.0-beta.5-linux-x64.tar.gz;
+        echo "642738beaea4ef1b9168446bc105267a2948a5e939537f5bd5afb48159140a44  sass_embedded-1.0.0-beta.5-linux-x64.tar.gz" | sha256sum -c;
+        tar -xvf sass_embedded-1.0.0-beta.5-linux-x64.tar.gz;
+        echo "$GITHUB_WORKSPACE/sass_embedded/" >> $GITHUB_PATH
+    - if: matrix.os == 'macos-latest'
+      name: Install dart-sass-embedded MacOS
+      run: |
+        curl -LJO https://github.com/sass/dart-sass-embedded/releases/download/1.0.0-beta.5/sass_embedded-1.0.0-beta.5-macos-x64.tar.gz;
+        echo "47b55a39126155f89fdfb8eea7c19ba976b3f6fadbdb6867e5582a18137bd180  sass_embedded-1.0.0-beta.5-macos-x64.tar.gz" | shasum -a 256 -c;
+        tar -xvf sass_embedded-1.0.0-beta.5-macos-x64.tar.gz;
+        echo "$GITHUB_WORKSPACE/sass_embedded/" >> $GITHUB_PATH
+    - if: matrix.os == 'windows-latest'
+      name: Install dart-sass-embedded Windows
+      run: |
+        curl -LJO https://github.com/sass/dart-sass-embedded/releases/download/1.0.0-beta.5/sass_embedded-1.0.0-beta.5-windows-x64.zip;
+        echo "5e65c0d8cbe038b6a120a3e7f390ad731708998f37c2de8ba565c51746a4588c  sass_embedded-1.0.0-beta.5-windows-x64.zip" | sha256sum -c;
+        unzip sass_embedded-1.0.0-beta.5-windows-x64.zip;
+        echo  "$env:GITHUB_WORKSPACE/sass_embedded/" | Out-File -FilePath $Env:GITHUB_PATH -Encoding utf-8 -Append
+    - name: Test
+      run: |
+        mage -v test
+        mage -v check;
+    - name: Build Docs
+      env:
+        HUGO_BUILD_TAGS: extended
+        HUGO_TIMEOUT: 31000
+        HUGO_IGNOREERRORS: error-remote-getjson
+      run: |
+        mage -v hugo
+        ./hugo -s docs/
+        ./hugo --renderToMemory -s docs/