v2.1.0

Features

• Adding X-Forwarded-For to instrumented fields | #91 | @paulosman
• Add request.header.accept_language field | #94 | @timcraft
• Support custom notifications based on a regular expression | #92 | @mrchucho

Fixes

• Properly pass options for Ruby 2.7 | #85 | @terracatta
• Fix regex substitution for warden and empty? errors for Rack | #88 | @irvingreid