Bump transformers to >=4.48 (#280)

*Issue #, if available:* addresses
https://github.com/amazon-science/chronos-forecasting/security/dependabot/1

*Description of changes:*


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pyproject.toml

@@ -12,7 +12,7 @@ license = { file = "LICENSE" }
 requires-python = ">=3.9"
 dependencies = [
     "torch>=2.0,<3",         # package was tested on 2.2
-    "transformers>=4.30,<4.48",
+    "transformers>=4.48,<5",
     "accelerate>=0.32,<1",
 ]
 classifiers = [