Update ESLint-related packages

R=jacktfranklin@chromium.org

No-Presubmit: True
Bug: none
Change-Id: I52dc24b12e350787085c5e3d131cface7ea87142
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3060705
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Paul Lewis <aerotwist@chromium.org>
diff --git a/node_modules/is-string/index.js b/node_modules/is-string/index.js
index 95b7050..5f77f03 100644
--- a/node_modules/is-string/index.js
+++ b/node_modules/is-string/index.js
@@ -11,7 +11,7 @@
 };
 var toStr = Object.prototype.toString;
 var strClass = '[object String]';
-var hasToStringTag = typeof Symbol === 'function' && typeof Symbol.toStringTag === 'symbol';
+var hasToStringTag = typeof Symbol === 'function' && !!Symbol.toStringTag;
 
 module.exports = function isString(value) {
 	if (typeof value === 'string') {