Bump uglifier from 4.1.20 to 4.2.0

[dependabot]

⚠️ Dependabot is rebasing this PR ⚠️

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---

Bumps uglifier from 4.1.20 to 4.2.0.

Changelog

Sourced from uglifier's changelog.

4.2.0 (25 September 2019)

• show code context for error messages (#167)
• defer initialisation of ExecJS context to fix #165

Commits

• 77226d1 Bump version to 4.2.0
• ac86e3e Update changelog
• 18f0419 Ignore Rubocop warning
• 3ff23bb Use new GitHub actions syntax
• 116444d Handle unexpected error messages better
• 9de67eb Defer initialisation of ExecJS context
• 990a6eb Expand abbreviations in variable names
• 4f65798 Refactor error context line option handling
• 5e544f5 Fix typo in method name
• 9958a20 Merge pull request #167 from eGust/err-context-lines
• Additional commits viewable in compare view

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[camallen]

Looks like uglifier update has lost execJS, report from the failed jenkins CI docker build

Step 14/16 : RUN (cd /rails_app && SECRET_KEY_BASE=1a bundle exec rake assets:precompile)
 ---> Running in 7d3d00e86f6c
�[91mrake aborted!
ExecJS::RuntimeUnavailable: Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes.
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs/runtimes.rb:58:in `autodetect'
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs.rb:5:in `<module:ExecJS>'
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs.rb:4:in `<top (required)>'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `require'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `block in require'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:240:in `load_dependency'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `require'
/usr/local/bundle/gems/uglifier-4.2.0/lib/uglifier.rb:5:in `<top (required)>'
/rails_app/config/application.rb:12:in `<top (required)>'
/rails_app/Rakefile:4:in `require'
/rails_app/Rakefile:4:in `<top (required)>'
/usr/local/bundle/gems/rake-13.0.3/exe/rake:27:in `<top (required)>'
/usr/local/bin/bundle:30:in `block in <main>'
/usr/local/bin/bundle:22:in `<main>'
(See full trace by running task with --trace)
�[0mThe command '/bin/sh -c (cd /rails_app && SECRET_KEY_BASE=1a bundle exec rake assets:precompile)' returned a non-zero code: 1

[camallen]

Looks like uglifier update has lost execJS, report from the failed jenkins CI docker build

Step 14/16 : RUN (cd /rails_app && SECRET_KEY_BASE=1a bundle exec rake assets:precompile)
 ---> Running in 7d3d00e86f6c
�[91mrake aborted!
ExecJS::RuntimeUnavailable: Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes.
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs/runtimes.rb:58:in `autodetect'
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs.rb:5:in `<module:ExecJS>'
/usr/local/bundle/gems/execjs-2.8.1/lib/execjs.rb:4:in `<top (required)>'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `require'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `block in require'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:240:in `load_dependency'
/usr/local/bundle/gems/activesupport-4.2.11.3/lib/active_support/dependencies.rb:274:in `require'
/usr/local/bundle/gems/uglifier-4.2.0/lib/uglifier.rb:5:in `<top (required)>'
/rails_app/config/application.rb:12:in `<top (required)>'
/rails_app/Rakefile:4:in `require'
/rails_app/Rakefile:4:in `<top (required)>'
/usr/local/bundle/gems/rake-13.0.3/exe/rake:27:in `<top (required)>'
/usr/local/bin/bundle:30:in `block in <main>'
/usr/local/bin/bundle:22:in `<main>'
(See full trace by running task with --trace)
�[0mThe command '/bin/sh -c (cd /rails_app && SECRET_KEY_BASE=1a bundle exec rake assets:precompile)' returned a non-zero code: 1

fixed by #3674