Fix README link to JEXL

The existing link is to the wrong JEXL. Apache's "Java Expression Language" is similar to, but not the same as the "JavaScript Expression Language" commonly in use at Mozilla.

README.md

@@ -1,6 +1,6 @@
 # jexl-rs [![CircleCI](https://circleci.com/gh/mozilla/jexl-rs/tree/main.svg?style=svg)](https://circleci.com/gh/mozilla/jexl-rs/tree/main)
 
-> [JEXL](https://commons.apache.org/proper/commons-jexl/) in Rust
+> [JEXL](https://www.npmjs.com/package/jexl) in Rust
 
 
 * jexl-eval: [![](https://meritbadge.herokuapp.com/jexl-eval)](https://crates.io/crates/jexl-eval) [![](https://docs.rs/jexl-eval/badge.svg?v=2)](https://docs.rs/jexl-eval)