docs: Fix GradVac links in README.md (#646)

* This should be reverted once GradVac is released.

Author: ValerianRey

README.md

@@ -281,7 +281,7 @@ TorchJD provides many existing aggregators from the literature, listed in the fo
 | [Constant](https://torchjd.org/stable/docs/aggregation/constant#torchjd.aggregation.Constant)              | [ConstantWeighting](https://torchjd.org/stable/docs/aggregation/constant#torchjd.aggregation.ConstantWeighting)        | -                                                                                                                                                                    |
 | [DualProj](https://torchjd.org/stable/docs/aggregation/dualproj#torchjd.aggregation.DualProj)              | [DualProjWeighting](https://torchjd.org/stable/docs/aggregation/dualproj#torchjd.aggregation.DualProjWeighting)        | [Gradient Episodic Memory for Continual Learning](https://arxiv.org/pdf/1706.08840)                                                                                  |
 | [GradDrop](https://torchjd.org/stable/docs/aggregation/graddrop#torchjd.aggregation.GradDrop)              | -                                                                                                                      | [Just Pick a Sign: Optimizing Deep Multitask Models with Gradient Sign Dropout](https://arxiv.org/pdf/2010.06808)                                                    |
-| [GradVac](https://torchjd.org/stable/docs/aggregation/gradvac#torchjd.aggregation.GradVac)              | [GradVacWeighting](https://torchjd.org/stable/docs/aggregation/gradvac#torchjd.aggregation.GradVacWeighting)                                                                                                                      | [Gradient Vaccine: Investigating and Improving Multi-task Optimization in Massively Multilingual Models](https://arxiv.org/pdf/2010.05874)                                                    |
+| [GradVac](https://torchjd.org/latest/docs/aggregation/gradvac#torchjd.aggregation.GradVac)              | [GradVacWeighting](https://torchjd.org/latest/docs/aggregation/gradvac#torchjd.aggregation.GradVacWeighting)                                                                                                                      | [Gradient Vaccine: Investigating and Improving Multi-task Optimization in Massively Multilingual Models](https://arxiv.org/pdf/2010.05874)                                                    |
 | [IMTLG](https://torchjd.org/stable/docs/aggregation/imtl_g#torchjd.aggregation.IMTLG)                      | [IMTLGWeighting](https://torchjd.org/stable/docs/aggregation/imtl_g#torchjd.aggregation.IMTLGWeighting)                | [Towards Impartial Multi-task Learning](https://discovery.ucl.ac.uk/id/eprint/10120667/)                                                                             |
 | [Krum](https://torchjd.org/stable/docs/aggregation/krum#torchjd.aggregation.Krum)                          | [KrumWeighting](https://torchjd.org/stable/docs/aggregation/krum#torchjd.aggregation.KrumWeighting)                    | [Machine Learning with Adversaries: Byzantine Tolerant Gradient Descent](https://proceedings.neurips.cc/paper/2017/file/f4b9ec30ad9f68f89b29639786cb62ef-Paper.pdf)  |
 | [Mean](https://torchjd.org/stable/docs/aggregation/mean#torchjd.aggregation.Mean)                          | [MeanWeighting](https://torchjd.org/stable/docs/aggregation/mean#torchjd.aggregation.MeanWeighting)                    | -                                                                                                                                                                    |