Pip package: BeautifulSoup dependency fix

Merge pull request #338 from strictdoc-project/develop

Bump version to 0.0.9

Python 3.9 support, parallelization-related fix, Child links in HTML export

• export/html: print children links, allow full left-right navigation
• document_finder: include case when intermediate folder has no .sdoc files
• parallelizer: fix hanging and zombie processes when child processes misbehave
• dsl/reader and cli/args: Python 3.9-related fixes

HTML export style improvements

• Sphinx HTML export: switch to guzzle theme, improve presentation of meta
• HTML export: fix presentation of sections on the DTR screen
• Grammar: some cleanups for consistency

Standalone HTML export and HTML style improvements

Merge pull request #295 from strictdoc-project/develop

Bump version to 0.0.6

Special Fields, Requirement Rationale, Excel Export

• Parsing requirements from Confluence source format
• Grammar: Rationale field
• Grammar: Special fields
• Excel export
• HTML export: Links between requirements work consistently on all document pages
• Invoke tasks: black and pylint

0.0.2

First Python package release using GitHub actions.