slightly adjust version in doc and setup.py (#438)

Signed-off-by: Clement Fuji Tsang <[email protected]>

docs/notes/installation.rst

@@ -11,7 +11,7 @@ Requirements
 ------------
 
 * Linux, macOS or Windows
-* Python >= 3.6 (3.6 or 3.7 recommended)
+* Python >= 3.6 (3.6 and 3.7 recommended for Windows)
 * CUDA >= 10.0 (with 'nvcc' installed)
 
 Dependencies
@@ -21,7 +21,7 @@ Dependencies
 * cython == 0.29.20
 * scipy >= 1.2.0
 * Pillow >= 8.0.0
-* usd-core == 20.11 (optional, required for USD related features such as visualization and importer / exporter)
+* usd-core >= 20.11 (optional, required for USD related features such as visualization and importer / exporter)
 
 Installation from source
 ------------------------

setup.py

@@ -132,7 +132,7 @@ def get_requirements():
         warnings.warn("usd-core is not compatible with python_version >= 3.10 "
                       "and won't be installed, please use supported python_version "
                       "to use USD related features")
-    requirements.append('usd-core==21.8; python_version < "3.10"')
+    requirements.append('usd-core>=20.11; python_version < "3.10"')
     if INCLUDE_EXPERIMENTAL:
         requirements.append('tornado==6.0.4')
         requirements.append('flask==1.1.2')