fix: bump actions/checkout to v5 (was still on the deprecated Node 20 runtime)

Author: Randy-R-code

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: oven-sh/setup-bun@v2
       - run: bun install --frozen-lockfile
       - run: bun run typecheck