chore(deps): update github artifact actions

Author: renovate[bot]

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Build with Maven
         run: mvn -B package
       - name: Upload jar
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: jar
           path: onyxia-api/target/*.jar
@@ -51,7 +51,7 @@ jobs:
       - uses: actions/checkout@v6
       - name: Download jar
         id: download
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: jar
           path: onyxia-api/target