fix: widen peer dep + move others to optional

Author: aminya

README.md

@@ -11,15 +11,15 @@ npm install --save-dev rollup-plugin-atomic
 You should also install the peer dependencies:
 
 ```
-"rollup": "2.21.0",
+"rollup": "^2"
 ```
 
 and the following (only those that you use are needed):
 
 ```
-"typescript": "^3.9.6",
-"coffeescript": "^1.12.7",
-"@babel/core": "^7.10.5",
+"typescript": "^4",
+"coffeescript": "^1",
+"@babel/core": "^7"
 ```
 
 ## Usage

package.json

@@ -38,10 +38,12 @@
     "rollup-plugin-visualizer": "^4.1.1"
   },
   "peerDependencies": {
-    "rollup": "2.31.0",
-    "typescript": "^4.0.3",
-    "coffeescript": "^1.12.7",
-    "@babel/core": "^7.12.1"
+    "rollup": "^2"
+  },
+  "optionalDependencies": {
+    "typescript": "^4",
+    "coffeescript": "^1",
+    "@babel/core": "^7"
   },
   "devDependencies": {
     "typescript": "^4.0.3",