Merge branch 'js/ci-make-sparse'

The CI gained a new job to run "make sparse" check.

* js/ci-make-sparse:
  ci/install-dependencies: handle "sparse" job package installs
  ci: run "apt-get update" before "apt-get install"
  ci: run `make sparse` as part of the GitHub workflow

diff --cc .github/workflows/main.yml
index e6f99e29a3db08f05c63edb3ddaa0757f2b8b748,224c46b6d6adb9778a80d3cc425b06178a1766fd..47876a4f02e2cb8785df1859d60a9cd7f83eee02
--- 1/.github/workflows/main.yml
--- 2/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@@ -282,9 -347,29 +282,29 @@@ jobs
        jobname: StaticAnalysis
      runs-on: ubuntu-18.04
      steps:
 -    - uses: actions/checkout@v1
 +    - uses: actions/checkout@v2
      - run: ci/install-dependencies.sh
      - run: ci/run-static-analysis.sh
+   sparse:
+     needs: ci-config
+     if: needs.ci-config.outputs.enabled == 'yes'
+     env:
+       jobname: sparse
+     runs-on: ubuntu-20.04
+     steps:
+     - name: Download a current `sparse` package
+       # Ubuntu's `sparse` version is too old for us
+       uses: git-for-windows/get-azure-pipelines-artifact@v0
+       with:
+         repository: git/git
+         definitionId: 10
+         artifact: sparse-20.04
+     - name: Install the current `sparse` package
+       run: sudo dpkg -i sparse-20.04/sparse_*.deb
+     - uses: actions/checkout@v2
+     - name: Install other dependencies
+       run: ci/install-dependencies.sh
+     - run: make sparse
    documentation:
      needs: ci-config
      if: needs.ci-config.outputs.enabled == 'yes'