update doctr to commit 56c8356 to fix BF16 mode (#1979)

Summary:
Update the version of `doctr` to include the fix in mindee/doctr#1342 for BF16 mode.

Remove the change of `rapidfuzz==2.15.1` in `requirements.txt` (#1555) since the version has been set in the model repo in the updated version (mindee/doctr#1176).

Pull Request resolved: #1979

Reviewed By: aaronenyeshi

Differential Revision: D50242780

Pulled By: xuzhao9

fbshipit-source-id: d8ed9164d463a1217114408106b2c745431bd159

torchbenchmark/models/doctr_det_predictor/requirements.txt

@@ -1,2 +1 @@
-git+https://github.com/mindee/doctr.git@acb9f64
-rapidfuzz==2.15.1
+git+https://github.com/mindee/doctr.git@56c8356