v4.0.6

📚 PR:

• Bump @types/node from 14.14.42 to 15.0.0 (#228)
• Bump tsd from 0.14.0 to 0.15.0 (#229)
• Bump actions/checkout from 2 to 2.3.4 (#231)
• docs: consume req.body in the form of key-value pairs (#233)
• ci: add Node 16 (#235)
• Remove unnecessary await keywords from documentations, tests and examples (#234)