only work with numpy 2.0 for python 3.9

Author: zm711

.github/workflows/io-test.yml

@@ -19,7 +19,7 @@ jobs:
       fail-fast: true
       matrix:
         python-version: ['3.9', '3.12']
-        numpy-version: ['1.26', '2.1']
+        numpy-version: ['1.26', '2.0']
     defaults:
       # by default run in bash mode (required for conda usage)
       run: