Update CI workflow to publish package to TestPyPI

.github/workflows/ci.yml

@@ -3,7 +3,7 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  build-package:
+  build-and-publish-package:
     runs-on: ubuntu-latest
     concurrency:
       group: ${{ github.event_name }}-${{ github.workflow }}-${{ github.ref_name }}-build-pkg
@@ -17,6 +17,12 @@ jobs:
 
       - run: make build
 
+      - name: Publish package to TestPyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          password: ${{ secrets.TEST_PYPI_API_TOKEN }}
+          repository-url: https://test.pypi.org/legacy
+
   lint:
     runs-on: ubuntu-latest
     concurrency: