Centralize CI/CD deps to a single requirements file, add twine as dependency

.ci/cicd-requirements.txt

@@ -0,0 +1,3 @@
+build~=1.3.0
+pytest~=9.0.2
+twine~=6.2.0

.github/workflows/deploy.yml

@@ -14,9 +14,12 @@ jobs:
       with:
         python-version: '3.x'
 
+    - name: Install CI/CD requirements
+      run:  |
+        pip install -r .ci/cicd-requirements.txt
+
     - name: Build sdist
       run: |
-        pip install build
         python -m build --sdist
 
     - name: Build wheels (macOS)

.github/workflows/python-package.yml

@@ -24,9 +24,12 @@ jobs:
       with:
         python-version: ${{ matrix.python }}
 
+    - name: Install CI/CD requirements
+      run: |
+        pip install -r .ci/cicd-requirements.txt
+
     - name: Install project
       run: |
-        pip install pytest
         pip install -e .
 
     - name: Test with pytest