Update transformers requirement from <4.19,>=4.1 to >=4.1,<4.20 (#5636)

* Update transformers requirement from <4.19,>=4.1 to >=4.1,<4.20

Updates the requirements on [transformers](https://github.com/huggingface/transformers) to permit the latest version.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](huggingface/transformers@v4.1.0...v4.19.0)

---
updated-dependencies:
- dependency-name: transformers
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update requirements.txt

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Dirk Groeneveld <dirkg@allenai.org>
Co-authored-by: Akshita Bhagia <akshita23bhagia@gmail.com>

requirements.txt

@@ -16,7 +16,7 @@ h5py>=3.6.0
 scikit-learn>=1.0.1
 scipy>=1.7.3
 pytest>=6.2.5
-transformers>=4.1,<4.19
+transformers>=4.1,<4.20
 sentencepiece>=0.1.96
 dataclasses;python_version<'3.7'
 filelock>=3.3,<3.8
@@ -28,6 +28,9 @@ huggingface_hub>=0.0.16
 dill>=0.3.4
 base58>=2.1.1
 
+# sacremoses should be a dependency of transformers, but it is missing, so we add it manually.
+sacremoses
+
 # Spacy depends on typer, and typer had a bug. This is how we make sure we get the fixed version of typer.
 typer>=0.4.1