Update gitignore (sorry)

electron/node_modules/lowercase-keys/index.d.ts

@@ -0,0 +1,16 @@
+/**
+Lowercase the keys of an object.
+
+@returns A new object with the keys lowercased.
+
+@example
+```
+import lowercaseKeys = require('lowercase-keys');
+
+lowercaseKeys({FOO: true, bAr: false});
+//=> {foo: true, bar: false}
+```
+*/
+declare function lowercaseKeys<T extends unknown>(object: {[key: string]: T}): {[key: string]: T};
+
+export = lowercaseKeys;