How to upgrade magento2 through command line.

Step 1: Disable your cache through command line.
            Example through command line : php bin/magento cache:disable

Step 2: Run cmd command -> Go to your magento folder
            For example, d://wamp/www/magento2

Step 3: Run : composer require magento/product-community-edition 2.0.5 --no-update

Step 4: Run: composer update
            It will ask for username and password. Provide username and password:

Note : In your developer account create your secure keys. Public is your username and private is your
           password.

 Step 4: Run:  php bin/magento setup:upgrade

Step 6: php bin/magento cache:enable

Enjoy your  magento has been updated

I have tested this code and upgrade from magento 2.0.4 to magento 2.0.5 and it is running successfully.