fix: downgrade GitHub Actions artifact actions from v5 to v4

The v5 version of actions/upload-artifact and actions/download-artifact
appears to not be available or stable yet. Downgrading to v4 which is
the stable version.

Author: RonnyPfannschmidt

.github/workflows/python-tests.yml

@@ -40,19 +40,19 @@ jobs:
         uses: hynek/build-and-inspect-python-package@v2
 
       - name: Download vcs-versioning packages
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v4
         with:
           name: Packages-nextgen-vcs-versioning
           path: dist/
 
       - name: Download setuptools-scm packages
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v4
         with:
           name: Packages
           path: dist/
 
       - name: Upload combined packages
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v4
         with:
           name: All-Packages
           path: dist/
@@ -121,7 +121,7 @@ jobs:
           git config --system gpg.program "C:\Program Files (x86)\gnupg\bin\gpg.exe"
         if: runner.os == 'Windows'
       - run: uv sync --group test --group docs --extra rich
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v4
         with:
           name: All-Packages
           path: dist
@@ -149,7 +149,7 @@ jobs:
       id-token: write
     needs: [test]
     steps:
-    - uses: actions/download-artifact@v5
+    - uses: actions/download-artifact@v4
       with:
         name: All-Packages
         path: dist
@@ -163,7 +163,7 @@ jobs:
     permissions:
       contents: write
     steps:
-    - uses: actions/download-artifact@v5
+    - uses: actions/download-artifact@v4
       with:
         name: All-Packages
         path: dist
@@ -180,7 +180,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-    - uses: actions/download-artifact@v5
+    - uses: actions/download-artifact@v4
       with:
         name: All-Packages
         path: dist