Fix some more yarn "unmet peer dependency" warnings

[edmorley]

Currently installing some of the individual lower-level presets on their own (as opposed to via the web/react/airbnb/... presets) still results in some yarn missing peerDependencies warnings.

These aren't harmful per-se due to the way Neutrino adjusts modules resolution, however similar to similar to #751 and #759 it would be good to suppress them, to avoid warnings spam/user confusion.

The reason some of these aren't seen when running yarn install in the monorepo root, is that it also installs devDependencies, which isn't the case when the packages are installed as a subdependency. These warnings can be made visible by running rm -rf yarn.lock node_modules/ packages/*/node_modules/ && yarn install --prod from the monorepo root (or alternatively using yarn pack and installing the packages via yarn add file:foo.tgz).

In addition there is one new warning from optimize-css-assets-webpack-plugin, which was due to a change they made recently in the 4.0.1 point release (so wasn't something we'd forgotten originally).

warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/eslint
     > eslint-loader@2.0.0" has unmet peer dependency "webpack@>=2.0.0 <5.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/font-loader
     > url-loader@1.0.1" has unmet peer dependency "webpack@^3.0.0 || ^4.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/font-loader
     > file-loader@1.1.11" has unmet peer dependency "webpack@^2.0.0 || ^3.0.0 || ^4.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/html-template
     > html-webpack-plugin@3.2.0" has unmet peer dependency "webpack@^1.0.0 || ^2.0.0 || ^3.0.0 || ^4.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/image-minify
     > imagemin-webpack@2.0.0" has unmet peer dependency "webpack@^2.0.0 || ^3.0.0 || ^4.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/style-loader
     > mini-css-extract-plugin@0.4.0" has unmet peer dependency "webpack@^4.4.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/style-minify
     > optimize-css-assets-webpack-plugin@4.0.1" has unmet peer dependency "webpack@^4.0.0".
warning "workspace-aggregator-a17d4f27-a7b5-4ae0-b4d2-253a2573d7ef
  > @neutrinojs/font-loader
     > url-loader 
        > schema-utils@0.4.5" has unmet peer dependency "webpack@^2.0.0 || ^3.0.0 || ^4.0.0".