Add separate tests for numpy 1 and numpy 2.

Author: tshead

.github/workflows/regression-tests.yml

@@ -13,6 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        numpy-version: ["<2.0.0", ">=2.0.0"]
 
     steps:
     - uses: actions/checkout@v3
@@ -25,6 +26,7 @@ jobs:
         sudo apt-get install ffmpeg ghostscript
         python -m pip install --upgrade pip
         pip install coveralls
+        pip install numpy${{ matrix.numpy-version }}
         pip install .[all]
     - name: Run tests
       run: |