Update markdown package to avoid deprecation warnings

.github/workflows/main.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v2

README.md

@@ -12,7 +12,7 @@ Requirements
 
 This plugin requires:
 
-* Python 3.9 or higher; and
+* Python 3.8 or higher; and
 * Pandoc 2.11 or higher [[Pandoc installation instructions](https://pandoc.org/installing.html)].
 
 By default, the plugin looks for a `pandoc` executable on your `PATH`. If you wish, [you may specify an alternative location for your `pandoc` executable](#customizing-the-path-for-the-pandoc-executable).

pyproject.toml

@@ -30,7 +30,7 @@ classifiers = [
 [tool.poetry.dependencies]
 python = ">=3.9.0,<4.0"
 pelican = ">=4.5"
-markdown = {version = "<=3.3.4", optional = true}
+markdown = ">=3.6"
 pyyaml = "^6.0.0"
 beautifulsoup4 = "^4.9.3"
 "ruamel.yaml" = "^0.17.32"
@@ -43,7 +43,7 @@ flake8-black = "^0.2.0"
 invoke = "^2.0"
 isort = "^5.12.0"
 livereload = "^2.6"
-markdown = "<=3.3.4"
+markdown = ">=3.6"
 pytest = "^6.0"
 pytest-cov = "^2.8"
 pytest-pythonpath = "^0.7.3"