Markdown-fenced-code-tabs-next

* **FIX**: Build failure due to [markdown 3.4+ package breaking change](https://python-markdown.github.io/changelog/#md_globals-keyword-deprecated-from-extension-api).

* **FIX**: Custom label capitalization issue.

* **FIX**: Build failure due to [markdown 3+ package breaking change](https://python-markdown.github.io/change_log/release-3.0/#safe_mode-and-html_replacement_text-keywords-deprecated).

* Avoid adding the `<div class="md-fenced-code-tabs"></div>` structure for single code blocks if the `single_block_as_tab` option is `True`.

* **FIX**: Fixed the Bootsrap templates

* **FIX**: Fixed the missing resources