Upgrade Dependencies for Gulp 4

[spencerbeggs]

Hi, Jussi,

This is just a quick PR that upgrades the dependencies in this module to squelch warnings during installation and also to avoid dependencies with know security issues. These are the issues resolved:

warning gulp-awspublish > gulp-util@2.2.20: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5
warning through2 > xtend > object-keys@0.4.0:
warning coveralls > request > hawk > hoek@2.16.3: The major version is no longer supported. Please update to 4.x or newer
warning coveralls > request > hawk > boom > hoek@2.16.3: The major version is no longer supported. Please update to 4.x or newer
warning coveralls > request > hawk > sntp > hoek@2.16.3: The major version is no longer supported. Please update to 4.x or newer
warning gulp > gulp-util@3.0.8: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5
warning gulp > vinyl-fs > graceful-fs@3.0.11: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js
warning gulp > vinyl-fs > glob-stream > minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp > vinyl-fs > glob-stream > glob > minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp > vinyl-fs > glob-watcher > gaze > globule > minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp > vinyl-fs > glob-watcher > gaze > globule > glob > minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp > vinyl-fs > glob-watcher > gaze > globule > glob > graceful-fs@1.2.3: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js
warning gulp-istanbul > gulp-util@2.2.20: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5
warning gulp-istanbul > istanbul > fileset > minimatch@0.4.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp-istanbul > istanbul > fileset > glob > minimatch@0.3.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp-mocha > gulp-util@2.2.20: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5
warning gulp-mocha > mocha > glob > minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp-mocha > mocha > glob > graceful-fs@2.0.3: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js
warning gulp-mocha > mocha > jade@0.26.3: Jade has been renamed to pug, please install the latest version of pug instead of jade

I also updated Gulp to v4 and as part of that upgraded the gulp-awspublish dependency to the latest version to avoids the deprecation of gulp-util: https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5

[spencerbeggs]

I also updated Travis to use Node 8 build environment. The tests were failing on Node 0.10. Gulp 4 has issue with v0.10, but that's pretty far out of date at this point, imo.

[jussi-kalliokoski]

Cool! Congratz on your first contribution and sorry that it took so long to come under my radar! This looks all good to me, aside from using different code formatting. I'd be highly in favor of adopting prettier, but it should be in a separate PR, as the scope is different.

[spencerbeggs]

Awesome. I pushed a commit that returns the code to the previous formatting.

[jussi-kalliokoski]

Published in https://github.com/jussi-kalliokoski/gulp-awspublish-router/commit/5b12050d564dd9960e41ef03e60732e90ab346f5 as v0.2.0 :tada:

Good work, thank you!!! 🙏