Tag v1.8.1 release.

mergify[bot] (8):
fix(tools): support both GitHub app tokens and PATs (backport #4869) (#4872)
chore(helm): update helm chart version (backport #4879) (#4880)
chore(helm): fix chart README (backport #4882) (#4884)
fix(cni): retry loading images (backport #4860) (#4861)
fix(kuma-cp): remove Dataplane for Pod without IP (backport #4964) (#4980)
fix(*): do not override source address when TP is not enabled (backport #4951) (#4961)
fix(kuma-cp): deep copy tags when gen. outbounds (backport #5070) (#5071)
fix(gateway): add support for retryOn (backport #5091) (#5098)