Update the NPM dependencies used at compile time.
Review Request #10625 — Created July 22, 2019 and submitted
Uglify-JS, and LessCSS. Our dependencies were locked to specific
versions, meaning we weren't benefiting from any bug fixes or security
updates (less of a problem in our case, given that this is purely
compile time of our own media, but still worth avoiding).
We now specify the latest minor release in each series we use, and
specify that newer minor releases are also acceptable. Right now, this
only actually affects babel-cli, babel-preset-es2015, and
Successfully built Djblets.