Explicitly install NumPy 1.x as we are not compatible with NumPy 2.x …

…yet.

.github/workflows/ci.yml

@@ -70,7 +70,7 @@ jobs:
         shell: python
       - name: Test
         run: |
-            pip install numpy ml_dtypes
+            pip install numpy<2 ml_dtypes
             cargo test --all-features
         # Not on PyPy, because no embedding API
         if: ${{ !startsWith(matrix.python-version, 'pypy') }}
@@ -104,7 +104,7 @@ jobs:
         continue-on-error: true
       - uses: taiki-e/install-action@valgrind
       - run: |
-            pip install numpy ml_dtypes
+            pip install numpy<2 ml_dtypes
             cargo test --all-features --release
         env:
           CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER: valgrind --leak-check=no --error-exitcode=1
@@ -119,7 +119,7 @@ jobs:
         continue-on-error: true
       - uses: taiki-e/install-action@cargo-careful
       - run: |
-            pip install numpy ml_dtypes
+            pip install numpy<2 ml_dtypes
             cargo careful test --all-features
 
   check-msrv:
@@ -195,7 +195,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install numpy
-        run: pip install numpy ml_dtypes
+        run: pip install numpy<2 ml_dtypes
       - uses: Swatinem/rust-cache@v2
         continue-on-error: true
       - uses: dtolnay/rust-toolchain@stable