chore(configuration): ♻️ remove packages for testing

remove `enzyme` and `jest` and its configuration

fix #24

.size-snapshot.json

@@ -24,13 +24,13 @@
     "gzipped": 6413
   },
   "react-epic-spinners.esm.js": {
-    "bundled": 81074,
-    "minified": 61646,
-    "gzipped": 6103,
+    "bundled": 81680,
+    "minified": 61855,
+    "gzipped": 6287,
     "treeshaked": {
       "rollup": {
-        "code": 44406,
-        "import_statements": 249
+        "code": 44281,
+        "import_statements": 73
       },
       "webpack": {
         "code": 52263

package.json

@@ -34,11 +34,7 @@
     "@rollup/plugin-replace": "2.3.3",
     "@types/react": "^16.9.51",
     "babel-plugin-transform-react-remove-prop-types": "0.4.24",
-    "enzyme": "^3.11.0",
-    "enzyme-adapter-react-16": "^1.15.5",
-    "jest": "^26.5.2",
     "prop-types": "^15.7.2",
-    "raf": "^3.4.1",
     "react-dom": "^16.13.1",
     "rollup": "^2.28.2",
     "rollup-plugin-size-snapshot": "^0.12.0",
@@ -54,10 +50,5 @@
     "dist",
     "typings/index.d.ts",
     "index.js"
-  ],
-  "jest": {
-    "setupFiles": [
-      "raf/polyfill"
-    ]
-  }
+  ]
 }