Cannot create cache directory /home/YOUR_USER/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache.
Method 1: Change Permission of Composer Cache Directory
To fix this error you have to change the ownership of your ".composer" directory.
sudo chown -R $USER $HOME/.composer
Method 2: Update Composer
The 2nd method is to update the composer to the latest version if possibile. To do that you need to run the self-update command.
sudo composer self-update