Some captions not using Markdown figure caption syntax

[matt-graham]

As part of reviewing episodes for #468 I noticed in some places figure captions are being included manually using HTML <p> tags - for example

python-intermediate-development/episodes/14-collaboration-using-git.md

Lines 312 to 314 in 73f53de

	{alt='Representation of Git\'s distributed version control system showing interactions between a central repository and two local repositories on developer machines, with arrows showing pushing from central repository to developer repositories, pulling from developer repositories to central repository. A self-connecting arrow on developer repository shows creating commits in local repository.' .image-with-shadow width="400px"}
	<p style="text-align: center;">Git - distributed version control system<br> From <a href="https://www.w3docs.com/learn-git/git-repository.html" target="_blank">W3Docs</a> (freely available)</p>

python-intermediate-development/episodes/14-collaboration-using-git.md

Lines 367 to 370 in 1dfe857

	{alt='Git feature branch workflow diagram' .image-with-shadow width="800px"}
	<p style="text-align: center;">Git feature branches<br>
	Adapted from <a href="https://sillevl.gitbooks.io/git/content/collaboration/workflows/gitflow/" target="_blank">Git Tutorial by sillevl</a> (Creative Commons Attribution 4.0 International License)</p>

It's not clear if this is required because of use of HTML tags in the caption text, but if not using the built-in figure caption syntax would probably be preferable.

Tasks:

• Check if figure captions can handle embedded HTML / Markdown.