requirements: update graph-scheduler requirement

Updates the requirements on [graph-scheduler](https://github.com/kmantel/graph-scheduler) to permit the latest version.
- [Release notes](https://github.com/kmantel/graph-scheduler/releases)
- [Commits](kmantel/graph-scheduler@v0.2.0...v1.1.1)

---
updated-dependencies:
- dependency-name: graph-scheduler
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,5 +1,5 @@
 autograd<1.5
-graph-scheduler>=0.2.0, <1.1.1
+graph-scheduler>=0.2.0, <1.1.2
 dill<=0.32
 elfi<0.8.4
 graphviz<0.21.0