Bump actions/download-artifact from 5 to 6

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

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/build-and-push-docker-image.yml

@@ -45,7 +45,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Fetch built PHAR from artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: pie-${{ github.sha }}.phar
 

.github/workflows/docs.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Build documentation
         run: .github/docs/build-docs.sh
       - name: Fetch built PHAR from artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: pie-${{ github.sha }}.phar
       - name: Verify the PHAR

.github/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
       contents: write
     steps:
       - name: Fetch built PHAR from artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: pie-${{ github.sha }}.phar
       - name: Verify the PHAR