Composer error : some dependencies are not available

[borgogelli]

$ composer update
Loading composer repositories with package information
Cannot create cache directory /home/borgo/.composer/cache/repo/https---repo.packagist.org/, or directory is not writable. Proceeding without cache
Info from https://repo.packagist.org: #StandWithUkraine
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Root composer.json requires fguillot/picodb, it could not be found in any version, there may be a typo in the package name.
  Problem 2
    - Root composer.json requires fguillot/picofeed, it could not be found in any version, there may be a typo in the package name.
  Problem 3
    - Root composer.json requires fguillot/simplelogger, it could not be found in any version, there may be a typo in the package name.
  Problem 4
    - Root composer.json requires fguillot/simple-validator, it could not be found in any version, there may be a typo in the package name.
  Problem 5
    - Root composer.json requires fguillot/simple-queue, it could not be found in any version, there may be a typo in the package name.

Are they private packages or is there a custom repository address we could add ?

[fguillot]

There is no need to run Composer manually. Dependencies are already included in the archive. If you still want to do it, you should run composer install instead of composer update.