travis-ci build error when composer.lock file is present in repository

[vsasvipul0605]

but removing composer.lock file stop deployment on heroku.

$ composer --version
Composer version 1.10.5 2020-04-10 11:44:22
0.21s

$ composer install
You are running composer with Xdebug enabled. This has a major impact on runtime performance. See https://getcomposer.org/xdebug
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

Problem 1
    - doctrine/instantiator 1.3.0 requires php ^7.1 -> your PHP version (5.3.29) does not satisfy that requirement.
    - doctrine/instantiator 1.3.0 requires php ^7.1 -> your PHP version (5.3.29) does not satisfy that requirement.
    - Installation request for doctrine/instantiator 1.3.0 -> satisfiable by doctrine/instantiator[1.3.0].

The command "composer install" failed and exited with 2 during .

Your build has been stopped.