src/goMain: show welcome page for 0.22.0

Tested by setting package.json's version to 0.22.0 and build
the extension.

Change-Id: I9f8d478a3a90b43a0042a163cf244f8fdb290d84
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/285838
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

src/goMain.ts

diff --git a/src/goMain.ts b/src/goMain.ts
index 122c8be..a0f69a1 100644
--- a/src/goMain.ts
+++ b/src/goMain.ts
@@ -581,7 +581,7 @@
 function showGoWelcomePage(ctx: vscode.ExtensionContext) {
 	// Update this list of versions when there is a new version where we want to
 	// show the welcome page on update.
-	const showVersions: string[] = [];
+	const showVersions: string[] = ['0.22.0'];
 
 	let goExtensionVersionKey = 'go.extensionVersion';
 	if (isInPreviewMode()) {