ci: run lint inside CI

Author: aminya

.github/workflows/ci.yml

@@ -60,4 +60,12 @@ jobs:
         run: |
           task test
           task test_release
-          task test_install
+          task test_install
+
+      - name: Lint
+        if: ${{ matrix.os == 'ubuntu-20.04' && matrix.compiler == 'gcc' }}
+        run: |
+          # TODO add to setup-cpp
+          python3 -m pip install --user cmakelint cmake-format
+
+          task lint