Initial TestPyPi CD workflow

.github/workflows/cd_testpypi.yml

@@ -0,0 +1,67 @@
+name: Publish to TestPyPI
+
+on:
+  push:
+    branches:
+      - main
+      - cd_pipeline
+
+jobs:
+  update-version-number:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Temporarily Update Version Number
+        run: |
+          # Get the current date in YYMMDD format
+          DATE=$(date +'%y%m%d')
+
+          # Update the version in pyproject.toml
+          sed -i "s/^version = \".*\"/version = \"0.${DATE}\"/" pyproject.toml
+  build:
+    name: Build distribution
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+      - name: Install pypa/build
+        run: >-
+          python3 -m
+          pip install
+          build
+          --user
+      - name: Build a binary wheel and a source tarball
+        run: python3 -m build
+      - name: Store the distribution packages
+        uses: actions/upload-artifact@v4
+        with:
+          name: python-package-distributions
+          path: dist/
+
+  publish-to-testpypi:
+    name: TestPyPI Release
+    needs:
+      - build
+    runs-on: ubuntu-latest
+
+    environment:
+      name: testpypi
+      url: https://test.pypi.org/p/mrpro
+
+    permissions:
+      id-token: write
+
+    steps:
+      - name: Download all the dists
+        uses: actions/download-artifact@v4
+        with:
+          name: python-package-distributions
+          path: dist/
+      - name: Publish to TestPyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          repository-url: https://test.pypi.org/legacy/