Bump torch from 1.8.1 to 1.13.1 in /solvers/enumerative

Bumps [torch](https://github.com/pytorch/pytorch) from 1.8.1 to 1.13.1.
- [Release notes](https://github.com/pytorch/pytorch/releases)
- [Changelog](https://github.com/pytorch/pytorch/blob/master/RELEASE.md)
- [Commits](pytorch/pytorch@v1.8.1...v1.13.1)

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

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

Author: dependabot[bot]

solvers/enumerative/requirements.txt

@@ -3,6 +3,6 @@ orderedset
 numpy
 astor
 sklearn
-torch==1.8.1
+torch==1.13.1
 transformers==2.11.0
 tensorboardX