src/goMain: correct showGoWelcomePage hard-coded version string

Remove the 'v' prefix.

Change-Id: I251055122f07c94a154f59bbda0cc7520db5cfd4
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/289698
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Robert Findley <rfindley@google.com>
diff --git a/src/goMain.ts b/src/goMain.ts
index 0dc656a..643847e 100644
--- a/src/goMain.ts
+++ b/src/goMain.ts
@@ -602,7 +602,7 @@
 	const showVersions: string[] = ['0.22.0'];
 	// TODO(hyangah): use the content hash instead of hard-coded string.
 	// https://github.com/golang/vscode-go/issue/1179
-	let goExtensionVersion = 'v0.22.0';
+	let goExtensionVersion = '0.22.0';
 	let goExtensionVersionKey = 'go.extensionVersion';
 	if (isInPreviewMode()) {
 		goExtensionVersion = '0.0.0';