feat: Support ESLint 7.x

[MichaelDeBoey]

ESLint v7.0.0 is released 🎉

devDependencies should be compatible with ESLint 7 too before we can merge this one:

• eslint-plugin-prettier (Support ESLint 7.x prettier/eslint-plugin-prettier#292)
  • Add tests for running ESLint 7 prettier/eslint-plugin-prettier#291
  • Release

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BREAKING CHANGE: Requires Node@^10.12.x || 12.x
BREAKING CHANGE: Requires ESLint@^7.x

Closes #44

[codecov-io]

Codecov Report

Merging #43 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master       #43   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           51        51           
=========================================
  Hits            51        51           

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[AdrieanKhisbe]

@MichaelDeBoey I'm going to have a look :)

But first I think I'll set up integration tests to ensure that eslint-plugin-json still works for eslint versions prior to the new 7 major if possible.

If it's not possible, and to avoid to support multiple version lines, it would be preferable IMO to make land #39 and #41 first, and address of #37 and #42

[AdrieanKhisbe]

@MichaelDeBoey after having worked on #46 to test different eslint major ranges,
it seems to be that this PR is not necessary to have plugin work on eslint-V7: it is already compatible, cf this build

(PS: typo was meant in original message referring this PR #43 rather than #46 🙈 )

[MichaelDeBoey]

Tested by #46