Update uglifyjs to latest version

[asturur]

This should be straightforward and necessary for newest syntax

[github-actions]

Code Coverage Summary

> fabric@5.1.0 coverage:report
> nyc report --reporter=lcov --reporter=text

-----------|---------|----------|---------|---------|-----------------------------------------------
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s                             
-----------|---------|----------|---------|---------|-----------------------------------------------
All files  |   83.05 |    75.98 |   85.69 |   82.78 |                                               
 fabric.js |   83.05 |    75.98 |   85.69 |   82.78 | ...,30850,30924,30935-31000,31123,31222,31458 
-----------|---------|----------|---------|---------|-----------------------------------------------

[ShaMan123]

I saw that there's a v3 that needs migrating to

[asturur]

I saw that there's a v3 that needs migrating to

isn't this one?
https://github.com/mishoo/UglifyJS
And exactly what we have?

i m confused too.

[asturur]

From our version and this one there are like 3 years of commits.