nestingReduce: invert if cond, replace body with `continue`, move old body after the statement (gocritic)

unlambda: replace `func(c *cli.Context) error {

typeAssertChain: rewrite if-else to type switch statement (gocritic)

`marshalling` is a misspelling of `marshaling` (misspell)

exported: type name will be used as validation.ValidationResponse by other packages, and that stutters; consider calling this Response (revive)

exported: type name will be used as validation.ValidationRequest by other packages, and that stutters; consider calling this Request (revive)

superfluous-else: if block ends with call to panic function, so drop this else and outdent its block (move short variable declaration to its own line if necessary) (revive)

superfluous-else: if block ends with call to panic function, so drop this else and outdent its block (move short variable declaration to its own line if necessary) (revive)

unused-parameter: parameter 'req' seems to be unused, consider removing or renaming it as _ (revive)