Update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/release-correspondence.yaml

@@ -73,7 +73,7 @@ jobs:
         
     - name: Upload artifacts (for non-tagged builds)
       if: "!startsWith(github.ref, 'refs/tags/correspondence-v')"
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
       with:
         name: correspondence-package-${{ env.VERSION }}
         path: |

.github/workflows/release-internalevents.yaml

@@ -66,7 +66,7 @@ jobs:
 
       - name: Upload artifacts (for non-tagged builds)
         if: "!startsWith(github.ref, 'refs/tags/internalevents-v')"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
         with:
           name: internalevents-package-${{ env.VERSION }}
           path: |