Fix/non integer rates (#116)

This resolves a bug of only integer rates being supported. via the CLI
`--rate` option. Adds support float rate values.

Author: thameem-abbas

src/guidellm/benchmark/profile.py

@@ -253,9 +253,9 @@ def from_standard_args(  # type: ignore[override]
         if not isinstance(rate, Sequence):
             rate = [rate]
 
-        if not all(r.is_integer() and r > 0 for r in rate):
+        if not all(isinstance(r, (float, int)) and r > 0 for r in rate):
             raise ValueError(
-                f"All rate values must be positive integers, received {rate}"
+                f"All rate values must be positive numbers, received {rate}"
             )
 
         if rate_type == "async":