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/apimachinery/pkg/labels/selector.go

@@ -74,9 +74,12 @@ type Selector interface {
 	RequiresExactMatch(label string) (value string, found bool)
 }
 
+// Sharing this saves 1 alloc per use; this is safe because it's immutable.
+var sharedEverythingSelector Selector = internalSelector{}
+
 // Everything returns a selector that matches all labels.
 func Everything() Selector {
-	return internalSelector{}
+	return sharedEverythingSelector
 }
 
 type nothingSelector struct{}
@@ -91,9 +94,12 @@ func (n nothingSelector) RequiresExactMatch(label string) (value string, found b
 	return "", false
 }
 
+// Sharing this saves 1 alloc per use; this is safe because it's immutable.
+var sharedNothingSelector Selector = nothingSelector{}
+
 // Nothing returns a selector that matches no labels
 func Nothing() Selector {
-	return nothingSelector{}
+	return sharedNothingSelector
 }
 
 // NewSelector returns a nil selector