Update swagger.yaml

[fgl82]

What is the problem this PR solves? Typo at the end of the file Checklist:

• [x] The swagger.yaml doc has been updated with any required changes
• [x] The openapi.yaml doc has been updated with any required changes

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: fgl82 / name: FGL82 (7b282018f9abf60b862e75de55f8c86e865649fa)

[pivotal-marcela-campo]

Hi @fgl82, thank you for your contribution. Could you sign the CLA in the comment above for us to merge this PR?

[fgl82]

Hello Marcela,

I signed, not sure it worked though, I still see the pending authorization

[fgl82]

Signing did work for https://github.com/openservicebrokerapi/servicebroker/pull/754, though, so not sure what's going on

[DerrickLFX]

/easycla

[pivotal-marcela-campo]

Thanks @DerrickLFX!

Bypassing 3 approving reviews requirement as this PR just fixes a mispelling.