Update dependency eslint-config-prettier to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
eslint-config-prettier	devDependencies	major	5.1.0 -> 6.0.0

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Release Notes

prettier/eslint-config-prettier

v6.0.0

Compare Source

• Changed: The CLI helper tool now considers [no-confusing-arrow] to conflict
  if you use the default value of its allowParens option. The default was
  changed to true in ESLint 6, which conflicts with Prettier.

  If the CLI helper tool gives you errors about this after upgrading, the
  solution is to change this:

  { "rules": { "no-confusing-arrow": ["error"] } }

  Into this:

  { "rules": { "no-confusing-arrow": ["error", { "allowParens": false }] } }

  The latter works in both ESLint 6 as well as in ESLint 5 and older.

• Improved: eslint --print-config usage instructions. The CLI tool help
  text as well as the documentation has been updated to suggest commands that
  work in ESLint 6.0 as well as in ESLint 5 and older. (Instead of eslint --print-config ., use eslint --print-config path/to/main.js.)

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Codecov Report

Merging #121 into master will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@ ## master #121 +/- ## ===================================== Coverage 100% 100% ===================================== Files 1 1 Lines 39 39 Branches 3 3 ===================================== Hits 39 39

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