fix: allow using custom importers

feat: upgrade postcss to 8.x

BREAKING CHANGE: upgrade postcss to 8.x

Co-authored-by: Edward Elric <SASUKE688848@gmail.com>
Co-authored-by: Ward Peeters <ward@coding-tech.com>

fix: make sourceMaps relative to the CSS output file (egoist#274)

Co-authored-by: Ward Peeters <ward@coding-tech.com>

fix(types): `options` is actually optional (egoist#311)

Co-authored-by: Ward Peeters <ward@coding-tech.com>

fix: extract css in same order as imports (egoist#295)

fix: Typing of namedExports option

build(deps): bump lodash from 4.17.15 to 4.17.19 (egoist#294)

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.15 to 4.17.19.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.15...4.17.19)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

fix: allow module config while using autoModules (egoist#281) (egoist…

…#292)

Refs developit/microbundle#653, developit/microbundle#617

build: tweak release action

fix: revert "feat: allow multiple entry files and outputs (egoist#264)…

…" (egoist#272)

This reverts commit 3ea986c.