MNT: (deps): Bump actions/upload-artifact from 3 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docs-conda.yml

@@ -88,7 +88,7 @@ jobs:
         popd
 
     - name: Upload docs as artifact
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: ${{ matrix.os }}-${{ matrix.python-version }}-docs
         path: |

.github/workflows/docs.yml

@@ -115,7 +115,7 @@ jobs:
 
     - name: Upload docs as artifact
       if: ${{ github.event_name == 'pull_request' }}
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: ${{ matrix.python-version }}-${{ matrix.dep-versions }}-docs
         path: |

.github/workflows/release.yml

@@ -31,7 +31,7 @@ jobs:
       run: python setup.py sdist bdist_wheel
 
     - name: Save built packages as artifact
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: packages-${{ runner.os }}-${{ steps.setup.outputs.python-version }}
         path: dist/