Cilium `master` officially supports up to K8s 1.26. However, the cloud
providers do not support creating managed clusters with K8s 1.26:

- AKS: 1.25 tops.
- EKS: 1.24 tops.
- GKE: 1.25 tops.

We pin CI workflows for the stable branch to use K8s 1.24 when creating
managed clustersas it is the lowest common supported version.

This version should be updated as appropriate when new K8s versions are
supported by the cloud providers.

Resources:

- AKS
  - Run `az aks get-versions --location westeurope --output table`
  - https://learn.microsoft.com/en-us/azure/aks/supported-kubernetes-versions

- EKS
  - Run `eksctl version -o json | jq -r '.EKSServerSupportedVersions[]'`
    (note: this asssumes `eksctl` is up to date, as this is static info)
  - https://docs.aws.amazon.com/eks/latest/userguide/kubernetes-versions.html
  - https://eksctl.io/usage/schema/#metadata-version

- GKE
  - Run `gcloud container get-server-config --format="yaml(channels)"`
  - https://cloud.google.com/kubernetes-engine/versioning
  - https://cloud.google.com/kubernetes-engine/docs/release-schedule

[Note:

The GKE workflow was already pinned to 1.24 to fix the CI, via
a77007aa44893be9894311e2546529c6e3968865 and later
1ce7f1f097731fa175a6bdee399413cc370450b5.]

Signed-off-by: Nicolas Busseneau <nicolas@isovalent.com>