build: bump core from 1b2fc42 to 8f7539a in the submodules group

Bumps the submodules group with 1 update: [core](https://github.com/tree-sitter/tree-sitter).


Updates `core` from `1b2fc42` to `8f7539a`
- [Release notes](https://github.com/tree-sitter/tree-sitter/releases)
- [Commits](tree-sitter/tree-sitter@1b2fc42...8f7539a)

---
updated-dependencies:
- dependency-name: core
  dependency-version: 8f7539af723621ff63541d54c09f4a6a05887839
  dependency-type: direct:production
  dependency-group: submodules
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]