Fix Tree-shaking support (#1247)

* improve Tree Shaking in ESM

Instead of bundling everything into a single ESM file, we generate every
single file as ESM. This is what we did in 1.4.x as well.

I would expect if your library had a single ESM file and you only used 1
function that the application you use it in correctly does the
tree-shakign for you. Apparantly a lot of applications are not properly
setup for this, so let's create multiple files instead.

* update changelog

package.json

@@ -42,6 +42,7 @@
     "@testing-library/jest-dom": "^5.11.9",
     "@types/node": "^14.14.22",
     "esbuild": "^0.14.11",
+    "fast-glob": "^3.2.11",
     "husky": "^4.3.8",
     "jest": "26",
     "lint-staged": "^12.2.1",