🌱 update compatibility matrix in README

[kranurag7]

What this PR does / why we need it:

• this commit updates compatibility matrix in the README

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):

Addresses: https://github.com/syself/cluster-api-provider-hetzner/pull/1311#issuecomment-2130628138

Special notes for your reviewer:

• v1.0.0-beta.34-35 I have used this to define a range which means beta.34 and beta.35 both supports 1.7.0 series of CAPI.

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• [ ] squash commits
• [ ] include documentation
• [ ] add unit tests