Add float64 to supported sensitve fields

[Lax77]

Description of your changes

Add support for float64 data type as sensitive field. We ran into an issue while upgrading provide-jet-datadog to latest release of terraform-provider-datadog as it introduced numeric sensitive field client_token_id of type float64

Fixes # https://github.com/crossplane/terrajet/issues/287

I have:

• [x] Read and followed Crossplane's [contribution process].
• [x] Run make reviewable to ensure this PR is ready for review.
• [ ] Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

• make generate on a jet provider

• make reviewable test on a jet provider

[Kerwood]

How is it going with this one ? Can we get this accepted ?