Swagger-parser 2.1.0 released!

• update core and parser v1 version to release (#1749)
• Changes in license and notice (#1744)
• bump parser v1 to 1.0.61-SNAPSHOT (#1740)
• fix for issue unexpectedNullExamples when flatten set to true (#1739)
• oas 3.1 dereference - don't dereference $anchor (#1736)
• oas 3.1 dereference - remove anchor merge (#1734)
• oas 3.1 dereference - fix visiting handling (#1732)
• support resolve/resolveFully with no location (#1731)
• OAS 3.1 Support (#1730)