[Snyk] Security upgrade webpack-cli from 3.2.3 to 4.0.0

[adamlaska]

Snyk has created this PR to fix 1 vulnerabilities in the npm dependencies of this project.

Snyk changed the following file(s):

• aspnetcore/tutorials/signalr-typescript-webpack/sample/3.x/package.json

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Regular Expression Denial of Service (ReDoS) SNYK-JS-CROSSSPAWN-8303230	828

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🦉 Regular Expression Denial of Service (ReDoS)

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