Remove windows requirement numpy <=1.19 (#38104)

* test if windows still need numpy <=1.19

* modify acoording to zhouwei's comment

python/requirements.txt

 requests>=2.20.0
-numpy>=1.13 ; python_version>="3.5" and platform_system != "Windows"
-numpy>=1.13, <=1.19.3 ; python_version>="3.5" and platform_system == "Windows"
+numpy>=1.20 ; python_version>="3.5"
 protobuf>=3.1.0
 Pillow
 six

python/unittest_py/requirements.txt

@@ -10,4 +10,3 @@ paddle2onnx>=0.8.2
 scipy>=1.6
 prettytable
 distro
-numpy>=1.20