Bump actions/upload-artifact from 5 to 6 (#4713)

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/build.yml

@@ -30,7 +30,7 @@ jobs:
           version: latest
           args: build --clean --snapshot --verbose
       - name: Upload flyctl for preflight
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: flyctl
           path: dist/default_linux_amd64_v1/flyctl

.github/workflows/release.yml

@@ -55,7 +55,7 @@ jobs:
           cat release.json | jq
           echo "sha_short=$(git rev-parse --short HEAD)" >> "$GITHUB_OUTPUT"
           echo "json=$(cat release.json)" >> "$GITHUB_OUTPUT"
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: build-artifacts
           path: |
@@ -132,7 +132,7 @@ jobs:
         env:
           RELEASE_JSON: ${{ needs.meta.outputs.json }}
         run: echo "$RELEASE_JSON" > ./dist/release.json
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: build-artifacts
           path: |