Move pretty-format to dependencies

Unfortunately as a side-effect of housing typings in this repo,
we need to explicitly add `pretty-format` as a dependency
since our types rely on it.

Note this project source code itself does not explicitly need
`pretty-format` but instead just its typings.

Author: samtsai

package.json

@@ -44,7 +44,8 @@
   "license": "MIT",
   "dependencies": {
     "@babel/runtime": "^7.10.2",
-    "@testing-library/dom": "^7.9.0"
+    "@testing-library/dom": "^7.9.0",
+    "pretty-format": "^25.5.0"
   },
   "devDependencies": {
     "@reach/router": "^1.3.3",
@@ -54,7 +55,6 @@
     "dtslint": "3.6.9",
     "kcd-scripts": "^6.2.0",
     "npm-run-all": "^4.1.5",
-    "pretty-format": "^25.5.0",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
     "rimraf": "^3.0.2"