v1.2.1

• Fixed XSD validation on Windows. Schema <xsd:import> resolution built a
  malformed file:// URL from backslash paths and keyed the schema lookup by
  a percent-encoded href that libxml2 normalises differently. Now uses
  pathToFileURL() and matches imported schemas by filename. Windows added
  to the CI matrix (thanks @muratkorkmaztr-cmyk, #6).
• Embedded factur-x.xml now uses the application/xml MIME type instead
  of the deprecated text/xml (RFC 7303), which current Factur-X conformance
  checkers flag (thanks @muratkorkmaztr-cmyk, #7).
• Expanded npm keywords (e.g. e-rechnung, pdfa, chorus-pro, un-cefact,
  spelling variants) so the package is easier to find on npm (#8).