Update dependency uglify-js to v3.7.7

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
uglify-js	dependencies	patch	3.7.6 -> 3.7.7

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Release Notes

mishoo/UglifyJS2

### [`v3.7.7`](https://togithub.com/mishoo/UglifyJS2/releases/v3.7.7) [Compare Source](https://togithub.com/mishoo/UglifyJS2/compare/v3.7.6...v3.7.7)  

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