Switch from jlpm to yarn

Co-authored-by: Ian Hunt-Isaak <[email protected]>

Author: jtpio

docs/source/examples/Widget Custom.ipynb

@@ -128,14 +128,14 @@
     "jupyter labextension develop . --overwrite\n",
     "\n",
     "# rebuild extension Typescript source after making changes\n",
-    "jlpm run build\n",
+    "yarn run build\n",
     "```\n",
     "\n",
     "It is also possible to rebuild the widget automatically when there is a new change, using the `watch` script:\n",
     "\n",
     "```bash\n",
     "# watch the source directory in one terminal, automatically rebuilding when needed\n",
-    "jlpm run watch\n",
+    "yarn run watch\n",
     "```\n",
     "\n",
     "\n",