fix chart name verification does not meet the specification

Signed-off-by: wawa0210 <xiaozhang0210@hotmail.com>

pkg/chartutil/create.go

@@ -36,7 +36,7 @@ import (
 // This regular expression is probably stricter than it needs to be. We can relax it
 // somewhat. Newline characters, as well as $, quotes, +, parens, and % are known to be
 // problematic.
-var chartName = regexp.MustCompile("^[a-zA-Z0-9._-]+$")
+var chartName = regexp.MustCompile("^[a-z0-9\\-]+$")
 
 const (
 	// ChartfileName is the default Chart file name.

pkg/chartutil/create_test.go

@@ -160,8 +160,12 @@ func TestCreate_Overwrite(t *testing.T) {
 func TestValidateChartName(t *testing.T) {
 	for name, shouldPass := range map[string]bool{
 		"":                              false,
-		"abcdefghijklmnopqrstuvwxyz-_.": true,
+		"abcdefghijklmnopqrstuvwxyz-_.": false,
-		"ABCDEFGHIJKLMNOPQRSTUVWXYZ-_.": true,
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ-_.": false,
+		"abcdefghijklmnopqrstuvwxyz":    true,
+		"abcdefghijklmnopqrstuvwxyz_":   false,
+		"abcdefghijklmnopqrstuvwxyz-":   true,
+		"abcdefghijklmnopqrstuvwxyz.":   false,
 		"$hello":                        false,
 		"Hellô":                         false,
 		"he%%o":                         false,