Bump actions/upload-artifact from 5 to 6 (#2138)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/cc-gha-implement.yml

@@ -294,7 +294,7 @@ jobs:
 
       - name: Upload logs
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: claude-output-implement-${{ github.event.issue.number }}
           path: /tmp/claude_output.log

.github/workflows/cc-gha-iterate.yml

@@ -255,7 +255,7 @@ jobs:
 
       - name: Upload Claude output logs
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: claude-output-iterate-${{ github.event.issue.number }}
           path: /tmp/claude_output.log

.github/workflows/cc-gha-plan.yml

@@ -208,7 +208,7 @@ jobs:
 
       - name: Upload Claude output logs
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: claude-output-plan-${{ github.event.issue.number }}
           path: /tmp/claude_output.log

.github/workflows/cc-gha-research.yml

@@ -188,7 +188,7 @@ jobs:
 
       - name: Upload Claude output logs
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: claude-output-research-${{ github.event.issue.number }}
           path: /tmp/claude_output.log

.github/workflows/pypi.yml

@@ -40,7 +40,7 @@ jobs:
           echo "Checking import and version number (on release)"
           venv-bdist/bin/python -c "import pymc_marketing as pmm; assert pmm.__version__ == '${{  github.ref_name }}' if '${{ github.ref_type }}' == 'tag' else pmm.__version__; print(pmm.__version__)"
           cd ..
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: artifact
           path: dist/*