Fix artifact creation, modernise tooling

.github/workflows/ci.yml

@@ -1,6 +1,11 @@
 name: Build
 
-on: [push, pull_request]
+on:
+    pull_request:
+    push:
+        branches: [main]
+        tags: ["*"]
+
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -61,8 +66,8 @@ jobs:
                 CIBW_ARCHS: ${{ matrix.arch }}
 
             - uses: actions/upload-artifact@v4
-              if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v')
               with:
+                  name: artifact-wheels
                   path: ./wheelhouse/*.whl
 
     build_sdist:
@@ -83,8 +88,8 @@ jobs:
               run: python setup.py sdist
 
             - uses: actions/upload-artifact@v4
-              if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v')
               with:
+                  name: artifact-source
                   path: dist/*.tar.gz
 
     pass:
@@ -103,8 +108,8 @@ jobs:
         steps:
             - uses: actions/download-artifact@v4
               with:
-                  name: artifact
                   path: dist
+                  merge-multiple: true
 
             - uses: pypa/gh-action-pypi-publish@release/v1
               with: