Update GitHub Artifact Actions

Author: renovate[bot]

.github/workflows/build.yaml

@@ -29,7 +29,7 @@ jobs:
       - uses: actions/attest-build-provenance@v3
         with:
           subject-path: 'bin/gawk_*'
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v6
         id: upload
         with:
           name: release_bundle

.github/workflows/release.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build_all
     steps:
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v7
         with:
           merge-multiple: true
       - run: shasum -a 256 gawk_* > SHA256.txt