Update sphinx requirement from 1.8.3 to 2.2.0

[dependabot-preview]

Updates the requirements on sphinx to permit the latest version.

Changelog

Sourced from sphinx's changelog.

Release 2.2.0 (released Aug 19, 2019)

Incompatible changes

• apidoc: template files are renamed to .rst_t
• html: Field lists will be styled by grid layout

Deprecated

• sphinx.domains.math.MathDomain.add_equation()
• sphinx.domains.math.MathDomain.get_next_equation_number()
• The info and warn arguments of
  sphinx.ext.autosummary.generate.generate_autosummary_docs()
• sphinx.ext.autosummary.generate._simple_info()
• sphinx.ext.autosummary.generate._simple_warn()
• sphinx.ext.todo.merge_info()
• sphinx.ext.todo.process_todo_nodes()
• sphinx.ext.todo.process_todos()
• sphinx.ext.todo.purge_todos()

Features added

• #5124: graphviz: :graphviz_dot: option is renamed to :layout:
• #1464: html: emit a warning if :confval:html_static_path and
  :confval:html_extra_path directories are inside output directory
• #6514: html: Add a label to search input for accessability purposes
• #5602: apidoc: Add --templatedir option
• #6475: Add override argument to app.add_autodocumenter()
• #6310: imgmath: let :confval:imgmath_use_preview work also with the SVG
  format for images rendering inline math
• #6533: LaTeX: refactor visit_enumerated_list() to use \sphinxsetlistlabels
• #6628: quickstart: Use https://docs.python.org/3/ for default setting of
  :confval:intersphinx_mapping
• #6419: sphinx-build: give reasons why rebuilded

Bugs fixed

• py domain: duplicated warning does not point the location of source code
• #6499: html: Sphinx never updates a copy of :confval:html_logo even if
  original file has changed
• #1125: html theme: scrollbar is hard to see on classic theme and macOS
• #5502: linkcheck: Consider HTTP 503 response as not an error
• #6439: Make generated download links reproducible
• #6486: UnboundLocalError is raised if broken extension installed
• #6567: autodoc: :confval:autodoc_inherit_docstrings does not effect to

... (truncated)

Commits

• bea7b5d Bump to 2.2.0 final
• 2e9f66b Update CHANGES for PR #6625
• 0df7ab0 Merge pull request #6625 from jakobandersen/6604_field_list_rendering
• 4ab751c Merge pull request #6657 from tk0miya/6605_crash_with_methodlikeobj
• 9dd7688 Fix field lists after switch to HTML5 writer
• 65e2fdc Fix #6605: autodoc: crashed when target code contains custom method-like objects
• 4a1df77 Update CHANGES for PR #6419
• a5d8e3d Merge pull request #6419 from larsoner/config
• 4e12d4b Merge pull request #6653 from jdufresne/importlib
• ecb1e76 Switch uses of import to importlib.get_module()
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
• @dependabot use these labels will set the current labels as the default for future PRs for this repo and language
• @dependabot use these reviewers will set the current reviewers as the default for future PRs for this repo and language
• @dependabot use these assignees will set the current assignees as the default for future PRs for this repo and language
• @dependabot use this milestone will set the current milestone as the default for future PRs for this repo and language
• @dependabot badge me will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in your Dependabot dashboard:

• Update frequency (including time of day and day of week)
• Automerge options (never/patch/minor, and dev/runtime dependencies)
• Pull request limits (per update run and/or open at any time)
• Out-of-range updates (receive only lockfile updates, if desired)
• Security updates (receive only security updates, if desired)

Finally, you can contact us by mentioning @dependabot.