[minor] Error from fse.copy is not handled correctly

[earshinov]

Got these warnings when trying to use the plugin for the first time:

[chrome #01-4] (node:28932) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, chmod 'C:\dev\e2e\results\styles'
[chrome #01-4] (node:28932) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
[chrome #01-4] (node:28932) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

As far as I can see, the primary suspect is fse.copy call at

protractor-screenshoter-plugin/index.js

Line 420 in 989f8e0

fse.copy(src, dest);

that needs to either be changed to fse.copySync or be given a callback to capture the error.

[earshinov]

There is a similar issue with mkdirp.sync, for example at

protractor-screenshoter-plugin/index.js

Line 644 in 989f8e0

mkdirp.sync(this.config.screenshotPath + '/screenshots', function(err) {

You should either use mkdirp instead of mkdirp.sync or transform the callback into a try..catch clause.

[azachar]

Hi there!

Feel free to provide a PR that will fix it. I am developing against mac and tests are run against a linux machine, so there might some specific issues with windows platform...

Cheers,
Andrej