ci: test: install lxml

Author: Willi Ballenthin

.github/workflows/test.yml

@@ -24,6 +24,10 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python }}
+    - name: Install lxml deps
+      run: sudo apt-get install -y libxml2-dev libxslt1-dev python-dev zlib1g-dev
+    - name: Install lxml
+      run: pip install lxml      
     - name: Install python-evtx
       run: pip install -e .
     - name: Run tests