feat: remove .mjs support (see #17)

package.json

@@ -4,12 +4,10 @@
   "versionS": "0.0.0-semantically-released",
   "description": "Server side rendering middleware for react-relay-network-modern",
   "files": [
-    "mjs",
     "lib",
     "node8"
   ],
   "main": "lib/index.js",
-  "module": "mjs/index.mjs",
   "repository": {
     "type": "git",
     "url": "https://github.com/relay-tools/react-relay-network-modern-ssr.git"
@@ -73,10 +71,8 @@
     ]
   },
   "scripts": {
-    "build": "npm run build-lib && npm run build-mjs && npm run build-node8",
+    "build": "npm run build-lib && npm run build-node8",
     "build-lib": "rimraf lib && BABEL_ENV=lib babel src --ignore __tests__,__mocks__ -d lib && BABEL_ENV=lib_server babel src/server.js -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-node8": "rimraf node8 && BABEL_ENV=node8 babel src --ignore __tests__,__mocks__ -d node8 && COPY_TO_FOLDER=node8 npm run build-flow",
     "build-flow": "echo `$1` && find ./src -name '*.js' -not -path '*/__*' | while read filepath; do cp $filepath `echo ./${COPY_TO_FOLDER:-lib}$filepath | sed 's/.\\/src\\//\\//g'`.flow; done",
     "lint": "eslint 'src/**/*.js'",