add lychee link checker to CI workflow

Author: terhorstd

.github/workflows/nestbuildmatrix.yml

@@ -102,16 +102,40 @@ jobs:
       - name: "Install dependencies"
         run: |
           sudo apt install python3-docutils
-          wget --progress=dot:mega "https://github.com/errata-ai/vale/releases/download/v2.15.2/vale_2.15.2_Linux_64-bit.tar.gz"
-          echo "7528175c995818bcb88b07574dd2e17c1aad13f5676880f43927bb8f673095aa  vale_2.15.2_Linux_64-bit.tar.gz" | sha256sum -c
-          tar -xzf vale_2.15.2_Linux_64-bit.tar.gz
+          wget --progress=dot:mega 'https://github.com/errata-ai/vale/releases/download/v2.15.2/vale_2.15.2_Linux_64-bit.tar.gz'
+          echo '7528175c995818bcb88b07574dd2e17c1aad13f5676880f43927bb8f673095aa  vale_2.15.2_Linux_64-bit.tar.gz' | sha256sum -c
+          tar -xzf 'vale_2.15.2_Linux_64-bit.tar.gz'
 
       - name: "Run vale..."
         run: |
           echo "Starting vale..."
           ./vale -v
           ./vale doc
 
+  lychee:
+    runs-on: "ubuntu-20.04"
+    steps:
+      - name: "Checkout repository content"
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      #- name: "Set up Python 3.x"
+      #  uses: actions/setup-python@v3
+      #  with:
+      #    python-version: 3.9
+
+      - name: "Install dependencies"
+        run: |
+          #sudo apt install python3-docutils
+          wget --progress=dot:mega 'https://github.com/lycheeverse/lychee/releases/download/v0.8.2/lychee-v0.8.2-x86_64-unknown-linux-gnu.tar.gz'
+          echo '12c27c9b6d551aea9178080d27de75ed26125b130722153399259432f723e606  lychee-v0.8.2-x86_64-unknown-linux-gnu.tar.gz' | sha256sum -c
+          tar -xzf 'lychee-v0.8.2-x86_64-unknown-linux-gnu.tar.gz'
+
+      - name: "Run lychee..."
+        run: |
+          ./lychee .
+
   pydocstyle:
     runs-on: "ubuntu-20.04"
     steps: