fix: Lower fastapi required version to fastapi>=0.115.2 (#193)

Fixes #101 🦕

Author: holtskinner

pyproject.toml

@@ -8,15 +8,15 @@ authors = [{ name = "Google LLC", email = "googleapis-packages@google.com" }]
 requires-python = ">=3.10"
 keywords = ["A2A", "A2A SDK", "A2A Protocol", "Agent2Agent"]
 dependencies = [
-    "fastapi>=0.115.12",
+    "fastapi>=0.115.2",
     "httpx>=0.28.1",
     "httpx-sse>=0.4.0",
     "google-api-core>=1.26.0",
     "opentelemetry-api>=1.33.0",
     "opentelemetry-sdk>=1.33.0",
     "pydantic>=2.11.3",
-    "sse-starlette>=2.3.3",
-    "starlette>=0.46.2",
+    "sse-starlette",
+    "starlette",
     "grpcio>=1.60",
     "grpcio-tools>=1.60",
     "grpcio_reflection>=1.7.0",