Update nokogiri requirement from = 1.11.7 to = 1.15.4#1926

dependabot[bot] wants to merge 1 commit intomainNexmo/station:mainfrom

dependabot/bundler/nokogiri-eq-1.15.4Nexmo/station:dependabot/bundler/nokogiri-eq-1.15.4Copy head branch name to clipboard