Toolset 3.2.0 released

[Alex Cabal]

Upgrade with `pipx upgrade standardebooks`.

While the version number bump is small, this is a big version.

In this version, we inline the Calibre code responsible for building
azw3 files directly into our source tree, removing our dependency on the
large Calibre binary. If you're not using Calibre for anything else, you
should be able to uninstall it after installing this version of the toolset.

This also introduces reproducible azw3 builds, which was not possible
when calling the Calibre binary.

Additionally, this release introduces a new local caching system for
images during build, so that subsequent builds of the same ebook can be
up to 75% faster.

The default maximum cache size is 50MB. You can change that by creating
a new configuration file. Copy `se/data/configuration.xml` into
`$XDG_CONFIG_HOME/se` and edit it to suit. (This is usually
`~/.config/se/` in Linux or `~/Library/Application Support/se` on Macs.

Full changelog:

# 3.2.0

## General

- Add configuration file support, and options for `se build` and `se
create-draft`

- More improvements to help text

## se build

- Use a local image cache to cache all rendered images during the build
process, speeding up subsequent builds

- Make AZW3 builds reproducible

- Include Calibre as vendored source to remove the dependency on the
Calibre binary app

- Fix Kobo builds on links with `&` entities. Thanks to Robin Whittleton

## se build-manifest

- Add all core epub MIME types

## se build-toc

- Improve error message

## se extract-ebook

- Make extracted AZW3 ebooks reproducible by removing the generated EPUB
from AZW3 extraction output

## se find-mismatched-diacritics

- Consider curly apostrophes and hyphens as parts of words

- Add the `--all` option to find all mismatches, even in short words

## se lint

- Improve t-003

- Recognize more common binary file extensions

- Update `se-lint-ignore.rng` regexes for cross-platform compatibility