src/goEnvironmentStatus: correct HOME/sdk path computation

Use os.homedir() to get the home directory path.
Windows does not use HOME environment variable.
This fixes the exception that occurred after successful Go download.

Change-Id: I9280ca9e040365ca0d8b9cb174b9ddec41b83fe0
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/245063
Reviewed-by: Brayden Cloud <bcloud@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/src/goEnvironmentStatus.ts b/src/goEnvironmentStatus.ts
index a1f77d9..1b78d6e 100644
--- a/src/goEnvironmentStatus.ts
+++ b/src/goEnvironmentStatus.ts
@@ -223,7 +223,7 @@
 			}
 
 			outputChannel.appendLine('Finding newly downloaded Go');
-			const sdkPath = path.join(process.env.HOME, 'sdk');
+			const sdkPath = path.join(os.homedir(), 'sdk');
 			if (!await pathExists(sdkPath)) {
 				outputChannel.appendLine(`SDK path does not exist: ${sdkPath}`);
 				throw new Error(`SDK path does not exist: ${sdkPath}`);