Release ES6

• Merge pull request #26 from etalab/es6-migration 2cab038
• Fix version mentions in README e60cc18
• Improve doc 78e614b
• Update for es6 resolution 6290b11
• Change to match description with real action in CI 057e68e
• Remove semi colon for linting 9bcf746
• Change to use node version 16+ (circleci & package.json) & list layers in cli 632aadb
• Update tests to ES6 and linting to latest xo rules e1be3c0
• Migrate to es6 3dc9e61

v0.9.1...v1.0.0