Updates from first deployment

git.sr.ht target was mangled.

py3-colour, builds.sr.ht, and py3-srht target versions had to be bumped
down. The first is due to a unit test error; the others are due to
unreleased versions that apparently upstream is keeping private.

Several APKBUILD files had to be updated for version numbers and
checksums. Notably, py3-pygments had to be bumped down a version. It
seems that an updated APKBUILD was pushed to the repo before an updated
apk was pushed to the mirror. I am choosing to follow the mirror as the
canonical target.

Reshaping repo

The repo is designed for use with an existing builds.sr.ht service.
Besides lacking that, I am more interested in a containerized workflow
powered by a Makefile. Package source code will live in `pkgsrc/`,
packages will be built into `pkg/`, and packaging keys will be
generated into `keys/`.

Alos trimmed the packages down to what I will build.