Update indexed-gzip requirement from ~=1.8.7 to ~=1.9.1

Updates the requirements on [indexed-gzip](https://github.com/pauldmccarthy/indexed_gzip) to permit the latest version.
- [Release notes](https://github.com/pauldmccarthy/indexed_gzip/releases)
- [Changelog](https://github.com/pauldmccarthy/indexed_gzip/blob/main/CHANGELOG.md)
- [Commits](pauldmccarthy/indexed_gzip@v1.8.7...v1.9.1)

---
updated-dependencies:
- dependency-name: indexed-gzip
  dependency-type: direct:production
...

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

pyproject.toml

@@ -21,7 +21,7 @@ dependencies = [
     "beautifulsoup4",  # to clean up HTML in DCAN executive summary outputs
     "bids-validator <= 1.14.7.post0",
     "h5py <= 3.12.1",  # for DCAN motion file
-    "indexed_gzip ~= 1.8.7",  # for loading imgs in nibabel
+    "indexed_gzip ~= 1.9.1",  # for loading imgs in nibabel
     "jinja2 ~= 3.1.2",  # for executive summary
     "joblib <= 1.4.2",
     "matplotlib ~= 3.9.0",