updated tch-rs to 0.13.0

[josephhajduk]

find replaced of_slice to from_slice as per
https://github.com/LaurentMazare/tch-rs/blob/008fff6cc0a91ecff274d1549c2dff25b8ca57a4/CHANGELOG.md

was having trouble running on m1 with 0.12.0, works with 0.13.0

[LaurentMazare]

A nice addition on 0.13.0 is that the torch-sys build script now emits the location of the libtorch shared library via some environment variable, this can be used by top level crates to use some link flags for binaries that remove the need for setting up LD_LIBRARY_PATH appropriately. A sample build script that does this would be diffusers-rs/build.rs.
(it's a bit sad to need this to be done in the top level crates but afaik there isn't an easy way to set some arbitrary linking flags for the final binaries from the library crates.

Also note that the automated libtorch download is now opt-out, you can get the old behavior with the specific cargo feature though probably better to avoid it if possible.

[guillaume-be]

Thank you @LaurentMazare for the note - these look like good changes indeed and will hopefully make the installation on mac / M1 targets easier. I have copied over the build script from diffusers-rs/build.rs, I hope that is fine.

[diptanu]

@josephhajduk @guillaume-be This is breaking the build of Indexify - https://github.com/diptanu/indexify

Any suggestions for how to fix it?

[josephhajduk]

I had to explicitly add a direct torch-sys dependency to my project with the download-libtorch feature. It didn't seem to work by adding the feature to the bert-rs dependency.

[guillaume-be]

@diptanu @josephhajduk could you please try to check the branch candidate at #382 without passing torch-sys as an additional dependency and let me know if this helps?

[diptanu]

@guillaume-be @josephhajduk I responded on the issue - PyO3 broke the build for me, I updated to the new master of rust-bert and added PyO3 which caused the confusion.

I see that new PR has been merged related to the libtorch download feature, will test it soon but I got around to solving the issue by adding a dependency to tch directly.