CI: Update latest released NumPy (1.26.4)

Author: WarrenWeckesser

.github/workflows/tests.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
-        numpy-version: ['1.20.3', '1.21.6', '1.22.4', '1.23.5', '1.24.4', '1.25.2', '1.26.2']
+        numpy-version: ['1.20.3', '1.21.6', '1.22.4', '1.23.5', '1.24.4', '1.25.2', '1.26.4']
         os: [ubuntu-latest, macos-12]
         exclude:
         - python-version: '3.10'
@@ -21,7 +21,7 @@ jobs:
         - python-version: '3.8'
           numpy-version: '1.25.2'
         - python-version: '3.8'
-          numpy-version: '1.26.2'
+          numpy-version: '1.26.4'
         - python-version: '3.12'
           numpy-version: '1.20.3'
         - python-version: '3.12'