chore(main): release 1.21.0

[hcloud-bot]

:robot: I have created a release beep boop

1.21.0 (2024-10-08)

Features

• add support & tests for Kubernetes 1.31 (#747) (c1e903c)
• drop tests for kubernetes v1.27 (#748) (0485215)
• helm: allow setting extra pod volumes via chart values (#744) (ad43445), closes #743
• service: Specify private ip for loadbalancer (#724) (4801f0e)

Bug Fixes

• populate ingress private ip when disable-private-ingress is false (#715) (8d29153)
• wrong version logged on startup (#729) (6b8cbf4)

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[jooola]

https://github.com/hetznercloud/hcloud-cloud-controller-manager/commit/8d291534a1adbb8bc9df0db7e5bd9f432ff2de6e includes some upgrade notes

[jooola]

https://github.com/hetznercloud/hcloud-cloud-controller-manager/pull/783#issuecomment-2469951439

We might need to drop k8s 1.28 before releasing

[apricote]

Replaced by #806.