Fix current changelog link in gh version

Also allow pre-release tags.

command/root.go

@@ -143,12 +143,11 @@ func colorableErr(cmd *cobra.Command) io.Writer {
 
 func changelogURL(version string) string {
 	path := "https://github.com/cli/cli"
-	r := regexp.MustCompile(`^v\d+\.\d+.\d+$`)
+	r := regexp.MustCompile(`^\d+\.\d+.\d+(-[\w.]+)?$`)
 	if !r.MatchString(version) {
 		return fmt.Sprintf("%s/releases/latest", path)
 	}
 
-	tag := version
-	url := fmt.Sprintf("%s/releases/tag/%s", path, tag)
+	url := fmt.Sprintf("%s/releases/tag/v%s", path, version)
 	return url
 }

command/root_test.go

@@ -6,13 +6,20 @@ import (
 )
 
 func TestChangelogURL(t *testing.T) {
-	tag := "v0.3.2"
+	tag := "0.3.2"
 	url := fmt.Sprintf("https://github.com/cli/cli/releases/tag/v0.3.2")
 	result := changelogURL(tag)
 	if result != url {
 		t.Errorf("expected %s to create url %s but got %s", tag, url, result)
 	}
 
+	tag = "0.3.2-pre.1"
+	url = fmt.Sprintf("https://github.com/cli/cli/releases/tag/v0.3.2-pre.1")
+	result = changelogURL(tag)
+	if result != url {
+		t.Errorf("expected %s to create url %s but got %s", tag, url, result)
+	}
+
 	tag = "0.3.5-90-gdd3f0e0"
 	url = fmt.Sprintf("https://github.com/cli/cli/releases/latest")
 	result = changelogURL(tag)