Remove .lgtm.yml and bungcip.better-toml (#1118)

* Remove deprecated lgtm.yml

* Remove 'better-toml' extension recommendation

Author: richardm-stripe

.lgtm.yml

@@ -1,7 +1,6 @@
 {
   "recommendations": [
     "ms-python.python",
-    "bungcip.better-toml",
     "EditorConfig.editorconfig"
   ]
 }