Fix Pandoc installation.

.github/workflows/publish.yml

@@ -15,6 +15,7 @@ jobs:
           python-version: '3.x'
       - name: Install Dependencies
         run: |
+          sudo apt-get install pandoc
           python -m pip install --upgrade pip
           pip install pypandoc
           pip install -r requirements.txt

setup.py

@@ -221,7 +221,7 @@ def long_description():
 
     try:
         import pypandoc
-        return pypandoc.convert(readme_path, 'rst')
+        return pypandoc.convert_file(readme_path, 'rst')
     except (IOError, ImportError):
         pass