Move eslint to ecma version 2020

[alexandrebodin]

What does it do?

Update eslint config to all ecma2020 syntax in the backend

Why is it needed?

To allow features available from node versions > 12

How to test it?

Provide information about the environment and the path to verify the behaviour.

Related issue(s)/PR(s)

Let us know if this is related to any issue/pull request

[codecov]

Codecov Report

Merging #14191 (f96ec5a) into main (ebac1f6) will decrease coverage by 0.09%.
The diff coverage is 33.33%.

❗ Current head f96ec5a differs from pull request most recent head 554671c. Consider uploading reports for the commit 554671c to get more accurate results

@@            Coverage Diff             @@
##             main   #14191      +/-   ##
==========================================
- Coverage   55.58%   55.49%   -0.10%     
==========================================
  Files        1275     1274       -1     
  Lines       31829    31829              
  Branches     5733     5738       +5     
==========================================
- Hits        17692    17662      -30     
- Misses      12323    12354      +31     
+ Partials     1814     1813       -1     

Flag	Coverage Δ
front	58.00% <33.33%> (-0.14%)	⬇️
unit	49.38% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...c/content-manager/components/DynamicTable/index.js	43.58% <0.00%> (-1.15%)	⬇️
...age/pages/ApiTokens/ListView/utils/tableHeaders.js	100.00% <ø> (ø)
packages/core/upload/admin/src/constants.js	100.00% <ø> (ø)
...ns/i18n/admin/src/components/ModalEdit/BaseForm.js	0.00% <0.00%> (ø)
...ges/SettingsPage/pages/ApiTokens/ListView/index.js	76.81% <100.00%> (+0.34%)	⬆️
...c/pages/SettingsPage/pages/Users/ListPage/index.js	81.66% <100.00%> (+0.31%)	⬆️
...ngsPage/pages/Users/ListPage/utils/tableHeaders.js	100.00% <100.00%> (ø)
...s/plugins/i18n/admin/src/hooks/useLocales/index.js	0.00% <0.00%> (-80.00%)	⬇️
...ns/i18n/admin/src/hooks/useDefaultLocales/index.js	0.00% <0.00%> (-76.20%)	⬇️
...ns/i18n/admin/src/components/LocaleSelect/index.js	93.10% <0.00%> (+31.03%)	⬆️

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