add numpy to dependencies in pyproject.toml

I had an error complaining that numpy was not found, and is needed for the helper functions which convert arrays.

pyproject.toml

@@ -26,7 +26,8 @@ classifiers = [
 ]
 
 dependencies = [
-    'Jpype1'
+    'Jpype1',
+    'numpy'
 ]
 
 [project.urls]