chore(deps): bump actions/download-artifact from 7 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/release.yml

@@ -108,12 +108,12 @@ jobs:
         with:
           tool: fd-find, just
       - name: Download bithesis.pdf
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: bithesis
           path: src
       - name: Download `*.cls`
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: cls
           path: src
@@ -152,7 +152,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Download *.cls
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: cls
           path: src
@@ -201,7 +201,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: Download bithesis.pdf
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: bithesis
           path: src
@@ -224,7 +224,7 @@ jobs:
             ${{ steps.git-cliff.outputs.content }}
 
       - name: Download handbooks
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: handbooks
           path: handbook
@@ -248,12 +248,12 @@ jobs:
         with:
           tool: just
       - name: Download bithesis.pdf
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: bithesis
           path: src
       - name: Download handbooks
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: handbooks
           path: handbook