fix: exclusive minimum and exclusive maximum are numbers

[mastermatt]

Reopening #1162 from @zobzn.
Originally, the PR couldn't be merged as the OpenAPI Validator didn't support the new spec. #1167 (comment)
More than three years on, I'm hoping this is no longer an issue.

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

Issue Number: #1162

What is the new behavior?

exclusiveMinimum and exclusiveMaximum can now be provided as either a bool or number, to support the newer spec.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

lgtm

[kamilmysliwiec]

Nope it's still broken #2994