Drop Node 12, bug fixes and small improvements

• chore: use the next tag for release 15acfa0
• refactor: extract CSRF exception to its own class 9835df1
• style: reformat source files 64fbf6d
• chore: remove npm-audit in favor of synk a2ec0b0
• chore: update dependencies 3c8c757
• fix: upgrade @poppinss/utils from 2.5.9 to 2.5.10 (#26) 0e67062
• chore(deps): bump highlight.js from 10.4.0 to 10.5.0 (#25) 5e629ef
• fix: upgrade helmet-csp from 3.2.0 to 3.3.1 (#24) 8497ba0
• refactor(xsrf-token): rename cookie name to all caps XSRF-TOKEN 789fd0d
• fix: upgrade ms from 2.1.2 to 2.1.3 (#21) a06d66e
• chore(deps): bump ini from 1.3.5 to 1.3.7 (#20) 937f668

v4.0.3...v5.0.0