Group `pbjson-types` substrait dependency with substrait

### Is your feature request related to a problem or challenge?

We're seeing PRs from dependabot trying to upgrade `pbjson-types` in `datafusion-substrait`:

- https://github.com/apache/datafusion/pull/20126

These are noise as we need to match the version from the `substrait` crate. Need to figure a way to exclude these updates whilst not affecting `pbjson-types` from other crates.

### Describe the solution you'd like

https://github.com/apache/datafusion/blob/b80bf2ca8ef74900fee96a1cc169bdedf53b36fc/datafusion/substrait/Cargo.toml#L45-L47

Somehow group `pbjson-types` and `substrait` dependencies here in dependabot, without affecting `pbjson-types` dependency in other crates in datafusion

https://github.com/apache/datafusion/blob/b80bf2ca8ef74900fee96a1cc169bdedf53b36fc/.github/dependabot.yml#L43-L47

- Is it possible to group by `Cargo.toml` manifest path instead of only names?

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by reading .github/dependabot.yml around lines 43-47 and datafusion/substrait/Cargo.toml around lines 45-47. Check Dependabot's grouping support for Cargo manifests and verify that grouping these dependencies affects only datafusion-substrait while leaving pbjson-types updates elsewhere unchanged. Done means the configuration prevents the reported noisy update without suppressing unrelated updates.

Written by the indexing model from the issue text.