0.5.0-alpha.4

• Maintenance updates
  • Update port to match ANTLR 4.9.0-opt (#492)
  • Fix errors with 'strict' mode compilation (#494, #496)
  • Update dependencies (#433, #441, #445, #469, #489)
  • Fix support for TypeScript 4 (#490)
  • Include .ts source files (#432)
• Bug fixes
  • Fix handling of text in CommonToken.fromToken (#415)