Use 2018 as target for extensions since we are now running on node 10

extensions/typescript-language-features/src/features/bufferSyncSupport.ts

@@ -157,8 +157,7 @@ class GetErrRequest {
 		};
 
 		client.executeAsync('geterr', args, _token.token)
-			.catch(() => true)
-			.then(() => {
+			.finally(() => {
 				if (this._done) {
 					return;
 				}