github/workflows: 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](https://github.com/actions/upload-artifact/compare/v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...
Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/code_size.yml

@@ -36,7 +36,7 @@ jobs:
       run: echo $PR_NUMBER > pr_number
     - name: Upload diff
       if: github.event_name == 'pull_request'
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: code-size-report
         path: |

.github/workflows/mpremote.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Build mpremote wheel
       run: cd tools/mpremote && python -m build --wheel
     - name: Archive mpremote wheel
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: mpremote
         path: |