ci: refresh apt lists before installing protobuf in docs build (#4636)

The docs deploy workflow installs protobuf-compiler without refreshing
apt
lists first. Ubuntu noble-updates replaced `protobuf
3.21.12-8.2ubuntu0.3`
with `.0.4`, so stale package lists in older runner images make `apt
install`
fail with 404 and exit code 100. Run `apt update` before installing,
matching
the other workflows.

.github/workflows/docs.yml

@@ -38,6 +38,7 @@ jobs:
         uses: actions/checkout@v6
       - name: Install dependencies needed for ubuntu
         run: |
+          sudo apt update
           sudo apt install -y protobuf-compiler libssl-dev
           rustup update && rustup default
       - name: Set up Python