fix: broken cjs build

Author: nodkz

package.json

@@ -66,7 +66,7 @@
   },
   "scripts": {
     "build": "npm run build-cjs && npm run build-mjs",
-    "build-cjs": "rimraf lib && babel src --ignore __tests__,__mocks__ -d lib && COPY_TO_FOLDER=lib npm run build-flow",
+    "build-cjs": "rimraf lib && BABEL_ENV=cjs babel src --ignore __tests__,__mocks__ -d lib && COPY_TO_FOLDER=lib npm run build-flow",
     "build-mjs": "rimraf mjs && BABEL_ENV=mjs babel src --ignore __tests__,__mocks__ -d mjs && yarn build-mjs-rename && COPY_TO_FOLDER=mjs npm run build-flow",
     "build-mjs-rename": "find ./mjs -name \"*.js\" -exec bash -c 'mv \"$1\" \"${1%.js}\".mjs' - '{}' \\;",
     "build-flow": "find ./src -name '*.js' -not -path '*/__*' | while read filepath; do cp $filepath `echo ./${COPY_TO_FOLDER:-lib}$filepath | sed 's/.\\/src\\//\\//g'`.flow; done",