ci: run "apt-get update" before "apt-get install"

The "sparse" workflow runs "apt-get install" to pick up a few necessary
packages. But it needs to run "apt-get update" first, or it risks trying
to download an old package version that no longer exists. And in fact
this happens now, with output like:

  2021-07-26T17:40:51.2551880Z E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/c/curl/libcurl4-openssl-dev_7.68.0-1ubuntu2.5_amd64.deb  404  Not Found [IP: 52.147.219.192 80]
  2021-07-26T17:40:51.2554304Z E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Our other ci jobs don't suffer from this; they rely on scripts in ci/,
and ci/install-dependencies does the appropriate "apt-get update".

Signed-off-by: Jeff King <[email protected]>
Acked-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

.github/workflows/main.yml

@@ -368,6 +368,7 @@ jobs:
       run: sudo dpkg -i sparse-20.04/sparse_*.deb
     - name: Install other dependencies
       run: |
+        sudo apt-get update -q &&
         sudo apt-get install -q -y libssl-dev libcurl4-openssl-dev libexpat-dev gettext zlib1g-dev
     - uses: actions/checkout@v2
     - run: make sparse