TL;DR

"You have to provide a username and password to commit to our repository. Use the --username and --password arguments."

This is what WP support on plugins@wordpress.org replied me on my email:

The problem

Dear WP,

I'm trying to update Mautic plugin as our user pointed out that it is outdated in your plugin repository. It is oudated, because it is PITA to make an update with this archaic, user unfriendly SVN. So I made a free half-day to update it instead of doing some valuable work. Long story short, here is where I got stuck:

$ svn ci -m "tracking pixel hidden, alt attr added"
Sending        trunk/wpmautic.php
Transmitting file data .svn: E195023: Commit failed (details follow):
svn: E195023: Changing file '/var/www/html/mautic-wordpress-svn/trunk/wpmautic.php' is forbidden by the server
svn: E175013: Access to '/!svn/txr/1189514-quup/wp-mautic/trunk/wpmautic.php' forbidden
svn: E175002: Additional errors:
svn: E175002: PUT of '/!svn/txr/1189514-quup/wp-mautic/trunk/wpmautic.php': 403 Forbidden

I consulted with Google obviously and found that other people are having hard time with this error as well:

• https://wordpress.org/support/topic/svn-plugin-commit-forbidden-by-the-server
• https://wordpress.org/support/topic/svn-access-to-is-forbidden
• https://wordpress.org/support/topic/subversion-says-403-forbidden-in-response-to-checkout-why
• https://wordpress.org/support/topic/unable-to-commit-to-plugin-svn-forbidden
• https://wordpress.org/support/topic/svn-commit-forbidden
• https://wordpress.org/support/topic/svn-commit-problem-403-forbidden
• https://wordpress.org/support/topic/cant-commit-to-svn-forbidden-by-server

Those are the first 7 links Google has found for me. Each with the same issue I'm having. None of them is solved. To make this information complete, I followed this tutorial to commit the changes:

https://wordpress.org/plugins/about/svn

Please, advice me how to commit the changes.

The solution

To commit to WP SVN use command like this:

$ svn ci -m "commit message here" --username your_username --password your_password

Ain't that simple? It would save some time if that was part of the documentation.

Another missing piece in the WP docs: tags

Before you make a new tag, make sure you updated the tag also in the file your_plugin.php!