hcloud-rust v0.15.0

Update to current state of Hetzner's API description.

Changes in the release:

• BREAKING: Add deprecation field to ServerType
  Note: The old boolean field deprecated is now considered deprecated.
• BREAKING: Add expose_routes_to_vswitch to Network and Subnet
• BREAKING: Add Alma variant to the OsFlavor enumeration to indicate AlmaLinux images
• Add resource-specific action endpoints (e.g. /certificates/actions)
• Add example for querying the images API
• Doc: Fix the usage of the term "Resource ID" vs "Action ID"
• Doc: Minor docstring updates