go.mod: update k8s deps to v0.26.2 (remove "replace" rule)

Replace rules are not inherited by consumers of buildx as a module, and as
such would default to use the v0.26.2 version. Removing the replace rules
also removes various (indirect) dependencies (although brings in some new
packages from k8s itself).

The "azure" and "gcp" authentication packages in k8s.io/go-client are now
no longer functional, so removing those imports.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/k8s.io/api/admissionregistration/v1/generated.proto

@@ -205,11 +205,13 @@ message Rule {
   // APIGroups is the API groups the resources belong to. '*' is all groups.
   // If '*' is present, the length of the slice must be one.
   // Required.
+  // +listType=atomic
   repeated string apiGroups = 1;
 
   // APIVersions is the API versions the resources belong to. '*' is all versions.
   // If '*' is present, the length of the slice must be one.
   // Required.
+  // +listType=atomic
   repeated string apiVersions = 2;
 
   // Resources is a list of resources this rule applies to.
@@ -227,6 +229,7 @@ message Rule {
   //
   // Depending on the enclosing object, subresources might not be allowed.
   // Required.
+  // +listType=atomic
   repeated string resources = 3;
 
   // scope specifies the scope of this rule.
@@ -249,6 +252,7 @@ message RuleWithOperations {
   // for all of those operations and any future admission operations that are added.
   // If '*' is present, the length of the slice must be one.
   // Required.
+  // +listType=atomic
   repeated string operations = 1;
 
   // Rule is embedded, it describes other criteria of the rule, like