migrate from v1.Endpoints to discoveryv1.EndpointSlices

[jkremser]

Fixes #1297

[Copilot]

Pull Request Overview

This PR migrates from Kubernetes v1.Endpoints to discovery/v1.EndpointSlices API to modernize the endpoint discovery mechanism. This is a breaking change that improves compatibility with newer Kubernetes versions but may break support for older clusters.

• Migration from v1.Endpoints to discoveryv1.EndpointSlices across the entire codebase
• Update RBAC permissions to access discovery.k8s.io API group instead of core v1
• Refactor endpoint data structure access patterns to use EndpointSlice.Endpoints instead of Endpoints.Subsets

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/checks/interceptor_websocket/interceptor_websocket_test.go	Remove version tag from test container image
scaler/queue_pinger_test.go	Update test imports and function signatures to use EndpointSlice
scaler/main.go	Update RBAC annotation for EndpointSlices API access
pkg/k8s/fake_endpoints.go	Refactor fake endpoint creation to use EndpointSlice structure
pkg/k8s/endpoints_test.go	Update tests to use EndpointSlice data structures and assertions
pkg/k8s/endpoints_cache_informer.go	Migrate informer to use EndpointSlice with label-based service selection
pkg/k8s/endpoints_cache_fake.go	Update fake cache implementation for EndpointSlice compatibility
pkg/k8s/endpoints_cache.go	Update interface signature to return EndpointSlice
pkg/k8s/endpoints.go	Migrate endpoint retrieval functions to use EndpointSlice API
operator/controllers/http/ping_test.go	Update test to handle EndpointSlice address structure
interceptor/proxy_handlers_integration_test.go	Update integration tests to use EndpointSlice objects
interceptor/main.go	Update RBAC annotation for EndpointSlices API access
interceptor/forward_wait_func_test.go	Update test helper functions to create EndpointSlice objects
interceptor/forward_wait_func.go	Update endpoint counting logic for EndpointSlice structure
config/scaler/role.yaml	Update RBAC role to access discovery.k8s.io/endpointslices
config/interceptor/role.yaml	Update RBAC role to access discovery.k8s.io/endpointslices
CHANGELOG.md	Document breaking change migration from v1.Endpoints to EndpointSlices

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