python-sdk: Support regions/vpc-availability endpoints

[mgwoj]

📝 Description

Added support regions/vpc-availability endpoints:

• List all vpc availability endpoints
• Get vpc availability endpoint

Also added support for get availability endpoint

✔️ How to Test

make test-unit

make TEST_SUITE="region" test-int

[Copilot]

Pull request overview

This PR adds support for VPC availability endpoints in the Python SDK, enabling users to query which regions support VPC functionality and what IPv6 prefix lengths are available. The PR also adds support for retrieving availability information for a specific region.

Changes:

• Added vpc_availability() and vpc_availability_get() methods to RegionGroup for listing and retrieving VPC availability data
• Added availability_get() method to RegionGroup for retrieving availability data for a specific region
• Added vpc_availability property to Region object for convenient access to VPC availability data
• Introduced RegionVPCAvailability dataclass to represent VPC availability information

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
linode_api4/groups/region.py	Added three new methods: availability_get, vpc_availability, and vpc_availability_get for retrieving region availability data
linode_api4/objects/region.py	Added vpc_availability property to Region class and RegionVPCAvailability dataclass
test/unit/groups/region_test.py	Added unit tests for new VPC availability and availability_get methods; cleaned up existing test assertions
test/unit/objects/region_test.py	Added unit test for Region.vpc_availability property
test/integration/models/region/test_region.py	Added comprehensive integration tests covering all three access patterns for VPC availability and the new availability_get method
test/fixtures/regions_vpc-availability.json	Added fixture data for VPC availability listing endpoint with pagination support
test/fixtures/regions_us-east_vpc-availability.json	Added fixture data for single region VPC availability endpoint

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[Copilot]

The available_ipv6_prefix_lengths values for us-east region are inconsistent between the two fixtures. In regions_vpc-availability.json (line 6), it's [52, 48], but in regions_us-east_vpc-availability.json (line 4), it's [52, 60]. These should be the same since they represent the same region. Please verify which values are correct and update one of the fixtures accordingly.

Suggested change

	"available_ipv6_prefix_lengths": [52, 60]
	"available_ipv6_prefix_lengths": [52, 48]