Fix small bug in mkdocs

[klwetstone]

• Fixes incorrect reference in watch of mkdocs.yml so building docs locally works
• Adds a makefile command for make docs-serve that serves the docs on a site locally

The standard mkdocs project setup actually has mkdocs.yml in the project root, and would build docs/ into site/ (as opposed to docs/docs/ into docs/site/). We've wrapped things into a subdirectory layer of docs/ that is non-standard to keep the root level cleaner (credit to Jay for the explanation!). To refer to the right place when building docs locally, we need:

watch:
    ../cloudpathlib

Instead of

watch:
   cloudpathlib

In mkdocs.yml

[github-actions]

🚀 Deployed on https://deploy-preview-178--gallant-agnesi-5f7bb3.netlify.app

[codecov]

Codecov Report

Merging #178 (53a3b06) into master (cce6a2f) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #178   +/-   ##
======================================
  Coverage    94.1%   94.1%           
======================================
  Files          21      21           
  Lines        1189    1189           
======================================
  Hits         1120    1120           
  Misses         69      69           

[klwetstone]

@jayqi this fixes the same issue in cloudpathlib that we just fixed in zamba if you have a chance to look it over. Thanks!

[jayqi]

Thanks @klwetstone! One minor change.

[klwetstone]

@jayqi updated! should be good to merge once the tests finish

[jayqi]

Works like a charm. Thanks @klwetstone!