Updated moment.js package.json version

[Streppel]

• [x] Try to keep the pull requests small; a pull request should try its very best to address only a single concern.
• [x] Make sure all tests pass and add additional tests for the code you submit.
• [x] Document your reasoning behind the changes. Explain why you wrote the code in the way you did; the code should explain what it does.
• [x] If there's an existing issue related to the pull request, reference to it by adding Fix #305, where 305 is the issue number.

Short description of what this resolves:

Running dependency_spy on the project gave the following vulnerability:

    Vulnerable: moment/runtime:^2.19.0
        Title: Regular Expression Denial of Service (ReDoS)
        Severity: Low
        Source: https://snyk.io/vuln/npm:moment:20170905

So this updates the package json to the latest version available on npm.

The list spits out other vulnerabilities as well but some of them require major version upgrades, so I didn't touch them.

The full list follows:

npm: lockfile ~> package-lock.json
    Vulnerable: bootstrap/runtime:3.3.7
        Title: Cross Site Scripting (XSS) in data-target attribute
        Severity: Unknown
        Source: https://ossindex.net/resource/package/7012139565/vulnerabilities

        Title: Cross-Site Scripting (XSS)
        Severity: Medium
        Source: https://snyk.io/vuln/npm:bootstrap:20160627

    Vulnerable: braces/runtime:1.8.5
        Title: Regular Expression Denial of Service (ReDoS)
        Severity: Low
        Source: https://snyk.io/vuln/npm:braces:20180219

    Vulnerable: chownr/runtime:1.1.1
        Title: Time of Check Time of Use (TOCTOU)
        Severity: Medium
        Source: https://snyk.io/vuln/npm:chownr:20180731

    Vulnerable: emailjs-mime-parser/runtime:2.0.5
        Title: Denial of Service (DoS)
        Severity: High
        Source: https://snyk.io/vuln/npm:emailjs-mime-parser:20180625

npm: manifest ~> package.json
    Vulnerable: bootstrap/runtime:^3.3.7
        Title: Cross Site Scripting (XSS) in data-target attribute
        Severity: Unknown
        Source: https://ossindex.net/resource/package/7012139565/vulnerabilities

        Title: Cross-Site Scripting (XSS)
        Severity: Medium
        Source: https://snyk.io/vuln/npm:bootstrap:20160627

    Vulnerable: lodash/runtime:^4.17.4
        Title: Prototype Pollution
        Severity: Low
        Source: https://snyk.io/vuln/npm:lodash:20180130

    Vulnerable: webpack-dev-server/development:^3.1.3
        Title: Information Exposure
        Severity: Low
        Source: https://snyk.io/vuln/SNYK-JS-WEBPACKDEVSERVER-72405

Changes proposed in this pull request:

• Updated moment.js package.json version

[dhoko]

Hey 👋

When you run npm install we already install the latest minor thx to this ^ ;)

[Streppel]

Oh, alright! I closed the PR :) thanks!