v0.3.0

Added

• actions/run-scripts: runs repository scripts by path, in order. Checks every path first and
  fails on a throw, a non-zero exit or a failing native command.
• actions/changelog: writes a Markdown changelog page from the git history, with pull request
  links and optional front matter.
• actions/node-scripts: installs a Node project and runs its package.json scripts in order,
  after building its local dependencies; browser: true provides a system Chromium.
• docs.yml inputs changelog, changelog-front-matter, node-project, node-scripts,
  node-dependencies and browser.
• Split-ActionList, Get-PackageManager and Install-NodePackage in the shared module.

Changed

• docs.yml: pre-build and post-build take script paths, one per line, instead of
  PowerShell code. A caller that passed code moves it into a script in its repository.
• docs-build: the template builder moves the site to output when it is set, so a
  repository whose scripts expect artifacts/docs keeps them unchanged.
• This repository's workflows call scripts in scripts/ instead of running inline code.