JAX 0.2.22: Replace all deprecated `jax.ops` operations with jnp's `at`
The `jax.ops.index_update` function used for in-place `jax.ndarray` operations was deprecated in [JAX 0.2.22](https://jax.readthedocs.io/en/latest/changelog.html?highlight=0.2.22#jax-0-2-22-oct-12-2021). It is advised that any in-place array modifications be made with [`jax.numpy.ndarray.at`](https://jax.readthedocs.io/en/latest/_autosummary/jax.numpy.ndarray.at.html). We should update the following scripts to conform to this new approach:

- [x] https://github.com/huggingface/transformers/blob/baab5e7cdf04c5b2cd209de4e9af6cb2c51a30d2/src/transformers/generation_flax_logits_process.py#L145
- [x] https://github.com/huggingface/transformers/blob/d3ae2bd3cf9fc1c3c9c9279a8bae740d1fd74f34/tests/generation/test_generation_flax_utils.py#L222
- [x] https://github.com/huggingface/transformers/blob/2596f95e8499bf350b18e1fa0492d38b6f8148fa/src/transformers/models/marian/modeling_flax_marian.py#L895
- [x] https://github.com/huggingface/transformers/blob/60b81dfa6faae3aa90c34a7df9304036f513d055/src/transformers/models/wav2vec2/modeling_flax_wav2vec2.py#L960
- [x] https://github.com/huggingface/transformers/blob/d25e25ee2b63ebfcd099deb689a5a7272574a10f/src/transformers/models/xglm/modeling_flax_xglm.py#L134
- [x] https://github.com/huggingface/transformers/blob/7732d0fe7a759c9844215920e9f1c5540eafb1a6/src/transformers/models/big_bird/modeling_flax_big_bird.py#L2127
- [x] https://github.com/huggingface/transformers/blob/2596f95e8499bf350b18e1fa0492d38b6f8148fa/src/transformers/models/blenderbot/modeling_flax_blenderbot.py#L886
- [x] https://github.com/huggingface/transformers/blob/2596f95e8499bf350b18e1fa0492d38b6f8148fa/src/transformers/models/blenderbot_small/modeling_flax_blenderbot_small.py#L898
- [x] https://github.com/huggingface/transformers/blob/2596f95e8499bf350b18e1fa0492d38b6f8148fa/src/transformers/models/bart/modeling_flax_bart.py#L925
- [x] https://github.com/huggingface/transformers/blob/2596f95e8499bf350b18e1fa0492d38b6f8148fa/src/transformers/models/mbart/modeling_flax_mbart.py#L949