fix: use default export (#368)

We mistakenly left `import` in our export map, which means CJS consumers
can't `require` chai-http right now.

This should fix it.

Author: 43081j

package.json

@@ -27,7 +27,7 @@
   "main": "./index.js",
   "exports": {
     ".": {
-      "import": "./index.js",
+      "default": "./index.js",
       "types": "./types/index.d.ts"
     }
   },