Added autoloader-suffix in composer config

[iamdharmesh]

Description of the Change

As described in #164, "Plugin asset/readme update" GH action is failing to deploy readme.txt because of autoload files of the composer. Composer generates new autoload files during composer install in GH action, which are different from the files commited in the svn repo of wp.org.

This PR adds autoloader-suffix in the composer config to generate the same autoload files with every install. So, the readme.txt file can deploy on minor changes or wp tested up to bumps.

Value of autoloader-suffix is in this format 10up{PLUGIN_NAME}{PLUGIN_VERSION} => 10upAutoshareForTwitterV111

Closes #164

Alternate Designs

We may use the IGNORE_OTHER_FILES option of GH action, but I feel autoloader-suffix is a better approach here, because with IGNORE_OTHER_FILES readme.txt file will be deployed with every change in it. (Think of readme update for plugin version bump merged in the trunk but we didn't added tag yet for release to deploy it on wp.org)

Possible Drawbacks

Not any

Verification Process

This can be verified with the successful deployment of readme.txt after the next release.

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Changelog Entry

Fixed - "Plugin asset/readme update" GH action failure.

Credits

Props @iamdharmesh