feat: Upgrade to React 17 (#826)

- Keep React 16 peerDependency for now

- Update storybook (for React 17 compatibility)

package.json

@@ -58,16 +58,16 @@
   },
   "homepage": "https://github.com/trussworks/react-uswds#readme",
   "peerDependencies": {
-    "react": "^16.x",
-    "react-dom": "^16.x",
+    "react": "^16.x || ^17.x",
+    "react-dom": "^16.x || ^17.x",
     "uswds": "2.8.0"
   },
   "devDependencies": {
     "@babel/core": "^7.10.5",
     "@babel/preset-react": "^7.10.4",
-    "@storybook/addon-docs": "^6.0.21",
-    "@storybook/addon-viewport": "^6.0.21",
-    "@storybook/react": "^6.0.21",
+    "@storybook/addon-docs": "^6.1.5",
+    "@storybook/addon-viewport": "^6.1.5",
+    "@storybook/react": "^6.1.5",
     "@storybook/storybook-deployer": "^2.8.6",
     "@testing-library/dom": "^7.22.3",
     "@testing-library/jest-dom": "^5.3.0",