remove 3.12 and fix 3.7 build

.github/workflows/regression.yml

@@ -16,7 +16,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', '3.11']
+    # 3.12 does not yet work because numpy removed numpy.distutils that pygacode relies on
 
     steps:
     - uses: actions/checkout@v4
@@ -42,7 +43,17 @@ jobs:
       run: |
         python3 -m pip install -r requirements.txt
 
-    - name: Install OMAS
+    # numpy is a build time dependency of pygacode
+    # but before 1.0 it did not specify it so we need to build without build isolation
+    # and manually install numpy 
+    - name: Install OMAS (Py 3.7)
+      if: ${{matrix.python-version == '3.7'}}
+      run: |
+        python3 -m pip install wheel
+        python3 -m pip install --no-build-isolation .[machine]
+
+    - name: Install OMAS (normal)
+      if: ${{matrix.python-version != '3.7'}}
       run: |
         python3 -m pip install .[machine]