changed the link to clone the library (#4725)

Doing `git clone -b v2 [email protected]:wix/react-native-navigation.git` gives me this: ``` fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists. ```
wix · Feb 13, 2019 · a9bbec8 · a9bbec8
1 parent 298ec43
commit a9bbec8
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/docs/docs/showcases.md b/docs/docs/showcases.md
@@ -19,7 +19,7 @@ It is a tab-based app and utilizes Split Layout for iOS tablets, 3D touch and mo
 The playground example is a place where we showcase and test all features of react-native-navigation.
 
 ```bash
-git clone -b v2 git@github.com:wix/react-native-navigation.git
+git clone https://github.com/wix/react-native-navigation
 cd react-native-navigation
 npm install
 npm run xcode # Opens XCode