message: feat: Add es2015 entries to the exports declaration to support Angular
  Based on Adds `es2015` entries to the `exports` declaration in the `package.json`.
diff: "exports": {
  ".": {
  "node": "./dist/cjs/index.js",
  + "es2015": "./dist/esm/index.js",
  "default": "./dist/esm5/index.js"
  },
  "./ajax": {
  "node": "./dist/cjs/ajax/index.js",
  + "es2015": "./dist/esm/ajax/index.js",
  "default": "./dist/esm5/ajax/index.js"
  },
  "./fetch": {
  "node": "./dist/cjs/fetch/index.js",
  + "es2015": "./dist/esm/fetch/index.js",
  "default": "./dist/esm5/fetch/index.js"
  },
  "./operators": {
  "node": "./dist/cjs/operators/index.js",
  + "es2015": "./dist/esm/operators/index.js",
  "default": "./dist/esm5/operators/index.js"
  },
  "./testing": {
  "node": "./dist/cjs/testing/index.js",
  + "es2015": "./dist/esm/testing/index.js",
  "default": "./dist/esm5/testing/index.js"
  },
  "./webSocket": {
  "node": "./dist/cjs/webSocket/index.js",
  + "es2015": "./dist/esm/webSocket/index.js",
  "default": "./dist/esm5/webSocket/index.js"
  },
  "./internal/*": {
  "node": "./dist/cjs/internal/*.js",
  + "es2015": "./dist/esm/internal/*.js",
  "default": "./dist/esm5/internal/*.js"
  },
  "./package.json": "./package.json"
  