Adopt Baseline Browserlist 2020 as default configuration

[sambacha]

Goals

Adopt Baseline Browserlsit configuration

NextJS supports Chrome v64, which was released in March 2018.

Cut the bloat and upgrade to at least 2020 chrome, v87

Baseline year feature sets

Baseline year feature sets include all the web platform features that were fully supported in the core browser set at the end of a given calendar year. To use a Baseline year feature set, add the year in the format /YYYY to the end of your extends statement:

Current NextJS Browserlist configuration

see https://nextjs.org/docs/architecture/supported-browsers#browserslist

{
  "browserslist": [
    "chrome 64",
    "edge 79",
    "firefox 67",
    "opera 51",
    "safari 12"
  ]
}

Baseline 2020 configuration

see https://github.com/web-platform-dx/browserslist-config-baseline#baseline-year-feature-sets

{
  "browserslist": [
    "extends browserslist-config-baseline/2020"
  ]
}

This equates to the following browserslist config:

{
  "browserslist": [
    "Chrome >= 87",
    "ChromeAndroid >= 87",
    "Edge >= 87",
    "Firefox >= 83",
    "FirefoxAndroid >= 83",
    "Safari >= 14",
    "iOS >= 14"
  ]
}

Non-Goals

Background

No need to add all this legacy browser support.

Proposal

Adopt supported browserlist as:

{
  "browserslist": [
    "Chrome >= 87",
    "ChromeAndroid >= 87",
    "Edge >= 87",
    "Firefox >= 83",
    "FirefoxAndroid >= 83",
    "Safari >= 14",
    "iOS >= 14"
  ]
}