chore(deps): update dependency go to v1.26.1

- Update GOLANG_VERSION in .github/env from 1.25.7 to 1.26.1
- Update go directive in go.mod from 1.25.7 to 1.26.1

Author: l-qing

.github/env

@@ -1,2 +1,2 @@
-GOLANG_VERSION=1.25.7
-GOLANGCI_LINT_VERSION=v2.5.0
+GOLANG_VERSION=1.26.1
+GOLANGCI_LINT_VERSION=v2.11.2

go.mod

@@ -1,6 +1,6 @@
 module helm.sh/helm/v4
 
-go 1.25.7
+go 1.26.1
 
 require (
 	github.com/AdaLogics/go-fuzz-headers v0.0.0-20230811130428-ced1acdcaa24

pkg/chart/common/util/jsonschema.go

@@ -83,7 +83,7 @@ func ValidateAgainstSchema(ch chart.Charter, values map[string]interface{}) erro
 		slog.Debug("chart name", "chart-name", chrt.Name())
 		err := ValidateAgainstSingleSchema(values, chrt.Schema())
 		if err != nil {
-			sb.WriteString(fmt.Sprintf("%s:\n", chrt.Name()))
+			fmt.Fprintf(&sb, "%s:\n", chrt.Name())
 			sb.WriteString(err.Error())
 		}
 	}
@@ -103,10 +103,10 @@ func ValidateAgainstSchema(ch chart.Charter, values map[string]interface{}) erro
 
 		subchartValues, ok := raw.(map[string]any)
 		if !ok {
-			sb.WriteString(fmt.Sprintf(
+			fmt.Fprintf(&sb,
 				"%s:\ninvalid type for values: expected object (map), got %T\n",
 				sub.Name(), raw,
-			))
+			)
 			continue
 		}