Migrate to React Testing Library (stripe#97)

* Migrate to React Testing Library

* Actually use Strict Mode in Strict Mode test

* Tweak test strategy for hooks under prop changes

* Revert "Tweak test strategy for hooks under prop changes"

This reverts commit dc99847.

package.json

@@ -67,7 +67,9 @@
     "@storybook/preset-typescript": "^1.2.0",
     "@storybook/react": "^5.2.6",
     "@stripe/stripe-js": "^1.2.0",
-    "@types/enzyme": "^3.10.4",
+    "@testing-library/jest-dom": "^5.8.0",
+    "@testing-library/react": "^10.0.4",
+    "@testing-library/react-hooks": "^3.2.1",
     "@types/jest": "^25.1.1",
     "@types/react": "^16.9.19",
     "@types/react-dom": "^16.9.5",
@@ -77,8 +79,6 @@
     "babel-eslint": "^10.0.3",
     "babel-jest": "^24.9.0",
     "babel-loader": "^8.0.6",
-    "enzyme": "3.10",
-    "enzyme-adapter-react-16": "^1.14.0",
     "eslint": "6.6.0",
     "eslint-config-airbnb": "18.0.1",
     "eslint-config-prettier": "^6.10.0",
@@ -94,6 +94,7 @@
     "react": "~16.9.0",
     "react-docgen-typescript-loader": "^3.6.0",
     "react-dom": "~16.9.0",
+    "react-test-renderer": "16.9",
     "rimraf": "^2.6.2",
     "rollup": "^1.27.0",
     "rollup-plugin-babel": "^4.3.3",