Revert 1.28 and 1.27 removal

.buildkite/bk.integration.pipeline.yml

@@ -338,6 +338,8 @@ steps:
             - "basic,slim,complete,service,elastic-otel-collector"
             - "wolfi,slim-wolfi,complete-wolfi,elastic-otel-collector-wolfi"
             version:
+            - v1.27.16
+            - v1.28.9
             - v1.29.8
             - v1.30.8
             - v1.31.0

.buildkite/pipeline.yml

@@ -227,6 +227,7 @@ steps:
               - "1.31.0"
               - "1.30.0"
               - "1.29.4"
+              - "1.28.9"
         retry:
           manual:
             allowed: true

pkg/testing/kubernetes/supported.go

@@ -38,6 +38,16 @@ var versions = []define.OS{
 		Type:    define.Kubernetes,
 		Version: "1.29.4",
 	},
+	// Kubernetes 1.28
+	{
+		Type:    define.Kubernetes,
+		Version: "1.28.9",
+	},
+	// Kubernetes 1.27
+	{
+		Type:    define.Kubernetes,
+		Version: "1.27.16",
+	},
 }
 
 // variants defines the list of variants and the image name for that variant.