Update mkdocs version

requirements.txt

-# Documentation static site generator & deployment tool
-mkdocs>=1.1.2
-
-# Add your custom theme if not inside a theme_dir
-# (https://github.com/mkdocs/mkdocs/wiki/MkDocs-Themes)
-#  mkdocs-material>=5.4.0
+# Documentation static site generator & deployment tool
+mkdocs>=1.5.3
+
+# Add your custom theme if not inside a theme_dir
+# (https://github.com/mkdocs/mkdocs/wiki/MkDocs-Themes)
+#  mkdocs-material>=5.4.0