ci: add native pr combiner

[JacobCoffee]

Description

• Updates config to combine dependabot PRs weekly

Other Option #2591

[shenxianpeng]

Copied the following from combine-prs README

As mentioned above is this README, a core reason why this Action exists is to "combine multiple Dependabot PRs into one". Work for this Action was completed before the GitHub Blog Post was published and the Dependabot Grouped Version Updates feature was released. While it may seem like this Action is no longer needed due to this feature, there are actually still quite a few use cases for this Action. The first one that is front of mind is that the PRs which Dependabot opens are grouped by package manager. This means that if you have a project that uses multiple package managers, you'll still end up with multiple PRs. This Action can be used to combine those PRs into a single one. You may also want to combine pull requests that are not related to Dependabot in anyway, which this Action can also do.

Since the rest only uses the pip package manager, it might be a good idea to use groups, as demonstrated in this repository:

https://github.com/python/pythondotorg/blob/main/.github/dependabot.yml#L28-L31