fix: XML escape package description

[mwegrzynek]

Packages with characters not legal in XML (for example &) in package description are rejected by Cholatey client, with malformed XML message. This pull request fixes that.

[google-cla]

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[joeyparrish]

@mwegrzynek, thank you for the fix! There are two issues that we need to resolve:

1. You need to sign the Contributor License Agreement (see the bot comment above). This is Google bureaucracy, and I can't do anything about it.
2. You need to add xml-escape to the dependencies with npm install xml-escape and then add package.json and package-lock.json to your PR.

Thanks!

[mwegrzynek]

Done!

[joeyparrish]

Published to NPM. Thanks for contributing!