ci: add luacheck linter

There was a linter check in test in `testing` workflow, but not in a
separate job.

After the patch a linter check is available in a separate job and the
previous step from `testing` workflow was deleted.

Closes #21

.github/workflows/check.yaml

@@ -0,0 +1,36 @@
+name: Run static analysis
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  run-static-analysis:
+    if: |
+      github.event_name == 'push' ||
+      github.event_name == 'pull_request' &&
+      github.event.pull_request.head.repo.full_name != github.repository
+
+    runs-on: ubuntu-22.04
+
+    steps:
+    - uses: actions/checkout@master
+
+    - name: Setup Tarantool CE
+      uses: tarantool/setup-tarantool@v3
+      with:
+        tarantool-version: '3.2.0'
+
+    - name: Setup tt
+      run: |
+        curl -L https://tarantool.io/release/3/installer.sh | sudo bash
+        sudo apt install -y tt
+        tt version
+
+    - name: Setup luacheck
+      run: make deps depname=lint
+
+    - run: echo $PWD/.rocks/bin >> $GITHUB_PATH
+
+    - name: Run static analysis
+      run: make check

.github/workflows/testing.yaml

@@ -95,13 +95,11 @@ jobs:
           tt version
 
       - name: Install requirements
-        run: make deps
+        run: make deps depname=coverage
         if: steps.cache-rocks.outputs.cache-hit != 'true'
 
       - run: echo $PWD/.rocks/bin >> $GITHUB_PATH
 
-      - run: make check
-
       - run: make test
 
       - name: Send code coverage to 'coveralls.io'