Release/v0.22.0 (#4107)

* fix/Avoid package.json import; (#4041)

* Added auto-generated config module `env/data.js` for importing package environment vars without importing the whole `package.json`;
Refactored `http.js` to use `env/data.js` instead of package.json;

* Added `env/data.js`;
Added `env/README.md`;

* Feat/export package version constant (#4065)

* Added auto-generated config module `env/data.js` for importing package environment vars without importing the whole `package.json`;
Refactored `http.js` to use `env/data.js` instead of package.json;

* Added `env/data.js`;
Added `env/README.md`;

* Export package version constant;

* Fixed cancelToken leakage; Added AbortController support; (#3305)

* Fixed cancelToken leakage;
Added AbortController support;

* Fixed typings;

* Documented `signal` option;

* Added processing of early cancellation using AbortController without sending a request;

Co-authored-by: Jay <jasonsaayman@gmail.com>

* Updating CI to run on release branches

* Fixed default transitional config for custom Axios instance; (#4052)

Refactored `/core/mergeConfig`;

Co-authored-by: Jay <jasonsaayman@gmail.com>

* Prepping v0.22.0 for release

* Updated date

Co-authored-by: Dmitriy Mozgovoy <robotshara@gmail.com>

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "axios",
   "main": "./dist/axios.js",
-  "version": "0.21.4",
+  "version": "0.22.0",
   "homepage": "https://axios-http.com",
   "authors": [
     "Matt Zabriskie"