Add GitHub actions (#267)

Add GitHub actions

.github/workflows/build-examples.yml

@@ -0,0 +1,75 @@
+name: Build Example PDF files
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0 # otherwise, there would be errors pushing refs to the destination repository.
+    - name: Setup pandoc
+      env:
+        PANDOC_VERSION: "2.11.2"
+      run: |
+        wget -qO- https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-linux-amd64.tar.gz | sudo tar xzf - --strip-components 1 -C /usr/local/
+    - name: Setup TexLive
+      env:
+        REMOTE: http://mirror.ctan.org/systems/texlive/tlnet
+        INSTALL: '/tmp/install-texlive'
+      run: |
+        mkdir -p ${INSTALL}
+        curl -sSL ${REMOTE}/install-tl-unx.tar.gz | tar -xzv -C $INSTALL --strip-components=1
+        sudo ${INSTALL}/install-tl -no-gui -profile .texlife.profile
+        VERSION=$($INSTALL/install-tl --version | grep 'version' | grep -o '[0-9]\{4\}')
+        PLATFORM=$($INSTALL/install-tl --print-platform)
+        TEXLIVE_DIR="/usr/local/texlive/${VERSION}"
+        TEXBIN="/usr/local/texlive/${VERSION}/bin/${PLATFORM}"
+        echo "${TEXBIN}" >> $GITHUB_PATH
+        sudo chown -hR $(whoami) "$TEXLIVE_DIR"
+    - name: Initialization for tlmgr
+      run: |
+        sudo apt-get update -qq && sudo apt-get install xzdec -y
+        tlmgr init-usertree
+    - name: Setup fonts and image convertion tool
+      run: sudo apt-get update -qq && sudo apt-get install fonts-noto-cjk poppler-utils -y
+    - name: Setup Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: '3.9'
+    - name: Install python filters
+      run: |
+        python -m pip install --upgrade pip
+        pip install pandoc-latex-environment
+    - name: Install LaTeX packages
+      run: | 
+        tlmgr install adjustbox background bidi csquotes footmisc footnotebackref fvextra mdframed pagecolor sourcecodepro sourcesanspro titling ulem upquote xurl
+        # trial and error
+        tlmgr install letltxmacro zref everypage framed collectbox
+        # packages needed for the template
+        tlmgr install xecjk filehook unicode-math ucharcat pagecolor babel-german ly1 mweights sourcecodepro sourcesanspro mdframed needspace fvextra footmisc footnotebackref background
+        # packages only needed for some examples (that include packages via header-includes)
+        tlmgr install awesomebox fontawesome5
+        # packages only needed for some examples (example boxes-with-pandoc-latex-environment-and-tcolorbox)
+        tlmgr install tcolorbox pgf etoolbox environ trimspaces   
+    - name: Build pdf files
+      run: cd examples && bash build-examples.sh && cd ..
+    - name: Archive production artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: build-files
+        path: |
+          examples/*/document.pdf
+          examples/*/preview.png
+    - name: Commit files
+      run: |
+        git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
+        git config --local user.name "github-actions[bot]"
+        git commit -m "Add changes" -a
+    - name: Push changes
+      uses: ad-m/github-push-action@master
+      if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        branch: ${{ github.ref }}