fix(deps)!: update module github.com/getkin/kin-openapi to v0.132.0

This is flagged as a breaking change as it could break consumers, as kin-openapi requires a minimum source compatibility (via go) of 1.22.

This is still a deprecated version of Go (which ran out of support on 2025-02-11), so is still outdated, and therefore shouldn't be /that/ breaking.

However, we should make it clear.

This also fixes an issue noted in 0 and 1, where the request body was not available to handlers after being processed by the openapi3filter.

Closes #5 (closed).