Convert cell_metadata index from integer to string for latest MERFISH…

… public data (#679)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Giovanni Palla <25887487+giovp@users.noreply.github.com>
Co-authored-by: LLehner <64135338+LLehner@users.noreply.github.com>

squidpy/read/_read.py

@@ -89,7 +89,7 @@ def visium(
     )
     coords.columns = ["in_tissue", "array_row", "array_col", "pxl_col_in_fullres", "pxl_row_in_fullres"]
     # https://github.com/scverse/squidpy/issues/657
-    coords.set_index(coords.index.astype(adata.obs.index.dtype), inplace=True)
+    coords.set_index(coords.index.astype("str"), inplace=True)
 
     adata.obs = pd.merge(adata.obs, coords, how="left", left_index=True, right_index=True)
     adata.obsm[Key.obsm.spatial] = adata.obs[["pxl_row_in_fullres", "pxl_col_in_fullres"]].values