Support Azure login page on WSL 1

The format reported by `/proc/version` differs between versions of WSL;
both report the text "Microsoft", albeit in different cases.

Signed-off-by: James Steele <[email protected]>

aci/login/helper.go

@@ -122,7 +122,7 @@ func isWsl() bool {
 		return false
 	}
 
-	return strings.Contains(string(b), "microsoft")
+	return strings.Contains(strings.ToLower(string(b)), "microsoft")
 }
 
 func randomString(prefix string, length int) string {