docs: remove --save (vuejs#263)

Mohamed Nainar · pikax · commit 1f2c85abb54c · 2020-04-19T10:09:34.000+01:00
diff --git a/README.md b/README.md
@@ -25,7 +25,7 @@
 **npm**
 
 ```bash
-npm install @vue/composition-api --save
+npm install @vue/composition-api
 ```
 
 **yarn**
