Resolve warnings with hogan.js and laravel-mix

We're getting the following warnings from hogan.js and laravel-mix:

warning eclipsefdn-hugo-solstice-theme > eclipsefdn-solstice-assets > hogan.js > mkdirp@0.3.0: Legacy versions of mkdirp are no longer supported. Please update to mkdirp 1.x. (Note that the API surface has changed to use Promises in 1.x.)

warning eclipsefdn-hugo-solstice-theme > eclipsefdn-solstice-assets > laravel-mix > node-libs-browser > url > querystring@0.2.0: The querystring API is considered Legacy. new code should use the URLSearchParams API instead.

warning eclipsefdn-hugo-solstice-theme > eclipsefdn-solstice-assets > laravel-mix > cssnano > cssnano-preset-default > postcss-svgo > svgo > stable@0.1.8: Modern JS already guarantees Array#sort() is a stable sort, so this library is deprecated. See the compatibility table on MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#browser_compatibility

Hogan hasn't had a release in 9 years and is unmaintained according to their GitHub.