[examples] Pin numpy version back for ray.
Issue
@@ -5,6 +5,9 @@ hydra-core==1.1.0
keras==2.6.0
matplotlib>=3.3.4
nevergrad>=0.4.3
+# NOTE(github.com/facebookresearch/CompilerGym/issues/750) Pin numpy version back
+# as workaround for numpy.object_ use in ray 1.9.0.
+numpy>=1.19.3,<1.20.0
opentuner>=0.8.5
pandas>=1.1.5
ray[default,rllib]==1.9.0
