[lldb-vscode] Add missing launchCommands entry in the package.json

Summary:
https://reviews.llvm.org/D65363 introduced the launchCommands argument. However, it did not add
a corresponding definition in the package.json

Reviewers: clayborg, labath, kusmour, aadsm

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D76529

lldb/tools/lldb-vscode/package.json

@@ -140,6 +140,11 @@
 									"description": "Commands executed just before the program is launched.",
 									"default": []
 							},
+							"launchCommands": {
+									"type": "array",
+									"description": "Commands that create a custom target instead of using lldb-vscode's default target creation.",
+									"default": []
+							},
 							"stopCommands": {
 									"type": "array",
 									"description": "Commands executed each time the program stops.",