php - composer vendor cannot be updated to the latest version of google/cloud-firestore ← (PHP)

I have installed composer recently on my ubuntu 1804 machine. I thought I have installed composer a few years back previously and I couldn't recall what I have done. Now it is not able to update to latest version. How could I fix that?

composer require google/cloud-firestore


Using version ^1.17 for google/cloud-firestore
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - don't install google/cloud-firestore v1.17.0|don't install google/cloud v0.74.0
    - don't install google/cloud-firestore v1.17.0|don't install google/cloud v0.74.1
    - don't install google/cloud-firestore v1.17.0|don't install google/cloud v0.74.0
    - Installation request for google/cloud-firestore ^1.17 -> satisfiable by google/cloud-firestore[v1.17.0].
    - Installation request for google/cloud ^0.74.0 -> satisfiable by google/cloud[v0.74.0, v0.74.1].

Installation failed, reverting ./composer.json to its original content.

edit : I am still looking around whether it is a permission issues or composer installation error. I will find out more from Composer documentation.

Solution:

My problem with it is the folder permission issue. When I set it to chmod 775, it works.