Update dgl requirement from <=2.0 to <=2.2.1

Updates the requirements on [dgl](https://github.com/dmlc/dgl) to permit the latest version.
- [Release notes](https://github.com/dmlc/dgl/releases)
- [Changelog](https://github.com/dmlc/dgl/blob/master/NEWS.md)
- [Commits](dmlc/dgl@v0.1.2...v2.2.1)

---
updated-dependencies:
- dependency-name: dgl
  dependency-version: 2.2.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pyproject.toml

@@ -48,7 +48,7 @@ ml-gpu = [
   "torchvision==0.19.0",
   "torchaudio==2.4.0",
   "molfeat==0.11.0",
-  "dgl<=2.0",
+  "dgl<=2.2.1",
   "dgllife>=0.3.2",
   "pytorch_geometric",
   "fcd_torch",
@@ -78,7 +78,7 @@ all = [
   "torchvision==0.19.0",
   "torchaudio==2.4.0",
   "molfeat==0.11.0",
-  "dgl<=2.0", 
+  "dgl<=2.2.1", 
   "dgllife>=0.3.2",
   "pytorch_geometric",
   "fcd_torch",