docs: update RC version in docs

Author: lukewalczak

docs/pages/1.getting-started.md

@@ -12,11 +12,11 @@ If you are looking for the latest stable version documentation, please check the
 Open a Terminal in your project's folder and run:
 
 ```sh
-yarn add react-native-paper@5.0.0-rc.6
+yarn add react-native-paper@5.0.0-rc.8
 ```
 or
 ```sh
-npm install react-native-paper@5.0.0-rc.6
+npm install react-native-paper@5.0.0-rc.8
 ```
 If you're on a vanilla React Native project, you also need to install and link [react-native-vector-icons](https://github.com/oblador/react-native-vector-icons).
 

docs/pages/10.migration-guide-to-5.0.md

@@ -17,11 +17,11 @@ Below you can find the most important information about the components whose API
 Currently v5 is a release candidate, which means it won't be installed by default from the `npm`. In order to do that, there is a need to explicitly pass package version during installation:
 
 ```sh
-yarn add react-native-paper@5.0.0-rc.6
+yarn add react-native-paper@5.0.0-rc.8
 ```
 or
 ```sh
-npm install react-native-paper@5.0.0-rc.6
+npm install react-native-paper@5.0.0-rc.8
 ```
 ## Theming