workflows: Fix apt installation in npm-update

GitHub's base VMs don't automatically refresh package indexes, so it can
happen that one of the package dependencies get out of date and are not
available on the mirrors any more.

Run `apt update` first to ensure that the workflow installs the latest
packages.

.github/workflows/npm-update.yml

@@ -9,7 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Set up dependencies
-        run: sudo apt-get install -y npm make
+        run: |
+          sudo apt update
+          sudo apt install -y npm make
 
       - name: Set up configuration and secrets
         run: |