Update BASE_URL,apkURL in APK

From unix/mac terminal open apk attached with release in vi editor and update BASE_URL using below steps.

1) Download APK file from release notes Assets section into <target_folder>. For example for v1.5.0 release download apk from https://github.com/Sunbird-Saral/Project-Saral/releases/download/v1.5.0/saral-app-unsigned-v1.5.0.apk

2) Open Terminal or shell in <target_folder> and use below vi command to open apk in vi editor.

vi saral-app-unsigned-v1.5.x.apk

3) Press Esc key and type /index.android.bundle and presss Enter key to locate assets/index.android.bundle file and press Enter key. This will open up the file for editing.

4) Search for TO_BE_REPLACED string and replace it with target BASE_URL. For example `https://saral-statename.anuvaad.org`

5) Press Esc key and enter :wq to save and go to file list the vi editor. Press Esc key and enter :q to quit the vi editor.

6) APK file should be updated with target BASE_URL with above steps.

7) Search for apkURL and change the value to actual Playstore URL based on the implementation.