Dependabot can't resolve your PHP dependency files.
As a result, Dependabot couldn't update your dependencies.
Your requirements could not be resolved to an installable set of packages.
Problem 1
- phpro/grumphp[v0.16.0, ..., v0.16.2] require composer-plugin-api ~1.0 -> found composer-plugin-api[2.0.0] but it does not match the constraint.
- Root composer.json requires phpro/grumphp ^0.16.0 -> satisfiable by phpro/grumphp[v0.16.0, v0.16.1, v0.16.2].
You are using Composer 2, which some of your plugins seem to be incompatible with. Make sure you update your plugins or report a plugin-issue to ask them to support Composer 2.
If you think the above is an error on Dependabot's side please don't hesitate to get in touch - we'll do whatever we can to fix it.