add transformers to requirements.txt due to new smolagents error at startup

Traceback (most recent call last):
File "/home/user/app/app.py", line 6, in <module>
from smolagents import CodeAgent, HfApiModel, tool, GradioUI
File "/usr/local/lib/python3.10/site-packages/smolagents/__init__.py", line 19, in <module>
from .agents import *
File "/usr/local/lib/python3.10/site-packages/smolagents/agents.py", line 37, in <module>
from .models import (
File "/usr/local/lib/python3.10/site-packages/smolagents/models.py", line 28, in <module>
from transformers import (
ModuleNotFoundError: No module named 'transformers'

requirements.txt

@@ -7,4 +7,5 @@ arize-phoenix
 opentelemetry-sdk
 opentelemetry-exporter-otlp
 openinference-instrumentation-smolagents
-biopython
+biopython
+transformers