[eslint config] [*] [docs] update the peer dep install command to dyn…

…amically look up the right version numbers when installing peer deps.

Fixes airbnb#956.

This command would be simpler if npm/npm#11213 is ever implemented.

packages/eslint-config-airbnb-base/README.md

@@ -12,7 +12,7 @@ We export two ESLint configurations for your usage.
 
 Our default export contains all of our ESLint rules, including ECMAScript 6+. It requires `eslint` and `eslint-plugin-import`.
 
-1. `npm install --save-dev eslint-config-airbnb-base eslint-plugin-import eslint`
+1. `PKG=eslint-config-airbnb-base npm info "$PKG" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install "$PKG"` (which produces and runs a command like `npm install --save-dev eslint-config-airbnb-base eslint@^3.0.1 eslint-plugin-import@^1.10.3` but with whatever the proper version numbers are)
 2. add `"extends": "airbnb-base"` to your .eslintrc
 
 ### eslint-config-airbnb-base/legacy

packages/eslint-config-airbnb/README.md

@@ -12,7 +12,7 @@ We export three ESLint configurations for your usage.
 
 Our default export contains all of our ESLint rules, including ECMAScript 6+ and React. It requires `eslint`, `eslint-plugin-import`, `eslint-plugin-react`, and `eslint-plugin-jsx-a11y`.
 
-1. `npm install --save-dev eslint-config-airbnb eslint-plugin-import eslint-plugin-react eslint-plugin-jsx-a11y eslint`
+1. `PKG=eslint-config-airbnb npm info "$PKG" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install "$PKG"` (which produces and runs a command like `npm install eslint-config-airbnb eslint@^2.9.0 eslint-plugin-jsx-a11y@^1.2.0 eslint-plugin-import@^1.7.0 eslint-plugin-react@^5.0.1` but with whatever the proper version numbers are)
 2. add `"extends": "airbnb"` to your .eslintrc
 
 ### eslint-config-airbnb/base