Billing_plan field deprecation - correction start date (#3765)

Co-authored-by: ci.datadog-api-spec <packages@datadoghq.com>

Author: api-clients-generation-pipeline[bot]

.generator/schemas/v1/openapi.yaml

@@ -20236,7 +20236,7 @@ components:
           type: string
         billing_plan:
           deprecated: true
-          description: The billing plan (metadata). (Deprecated from May 2026)
+          description: The billing plan (metadata). (Deprecated from June 2026)
           type: string
         end_date:
           description: Shows the last date of usage.

api/datadogV1/model_usage_billable_summary_hour.go

@@ -16,7 +16,7 @@ type UsageBillableSummaryHour struct {
 	AccountName *string `json:"account_name,omitempty"`
 	// The account public ID.
 	AccountPublicId *string `json:"account_public_id,omitempty"`
-	// The billing plan (metadata). (Deprecated from May 2026)
+	// The billing plan (metadata). (Deprecated from June 2026)
 	// Deprecated
 	BillingPlan *string `json:"billing_plan,omitempty"`
 	// Shows the last date of usage.