actions: move lint checks into their own job

.github/workflows/test_fast.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
     strategy:
-      fail-fast: false # Don't let a failed MacOS run stop the Ubuntu runs
+      fail-fast: false # don't stop on first failure
       matrix:
         os: ['ubuntu-latest']
         python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
@@ -39,7 +39,7 @@ jobs:
         if: startsWith(matrix.os, 'ubuntu')
         run: |
           sudo apt-get update
-          sudo apt-get install -y shellcheck sqlite3
+          sudo apt-get install -y sqlite3
 
       - name: Install
         run: |
@@ -48,22 +48,6 @@ jobs:
       - name: Configure git  # Needed by the odd test
         uses: cylc/release-actions/configure-git@v1
 
-      - name: Check changelog
-        if: startsWith(matrix.os, 'ubuntu')
-        run: towncrier build --draft
-
-      - name: Style
-        if: startsWith(matrix.os, 'ubuntu')
-        run: |
-          flake8
-          etc/bin/shellchecker
-
-      # note: exclude python 3.10+ from mypy checks as these produce false
-      # positives in installed libraries for python 3.7
-      - name: Typing
-        if: startsWith(matrix.os, 'ubuntu') && startsWith(matrix.python-version, 3.9)
-        run: mypy
-
       - name: Doctests
         timeout-minutes: 4
         run: |
@@ -74,12 +58,6 @@ jobs:
         run: |
           pytest tests/unit
 
-      - name: Bandit
-        if: ${{ matrix.python-version == '3.7' }}
-        # https://github.com/PyCQA/bandit/issues/658
-        run: |
-          bandit -r --ini .bandit cylc/flow
-
       - name: Integration Tests
         timeout-minutes: 6
         run: |
@@ -108,6 +86,45 @@ jobs:
         if: startsWith(matrix.python-version, '3.10')
         run: pytest -m linkcheck --dist=load tests/unit
 
+  lint:
+    runs-on: 'ubuntu-latest'
+    timeout-minutes: 10
+    steps:
+      - name: Apt-Get Install
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y shellcheck
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # note: exclude python 3.10+ from mypy checks as these produce false
+      # positives in installed libraries for python 3.7
+      - name: Configure Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.9
+
+      - name: Install
+        run: |
+          pip install -e ."[tests]"
+
+      - name: Flake8
+        run: flake8
+
+      - name: Bandit
+        run: |
+          bandit -r --ini .bandit cylc/flow
+
+      - name: Shellchecker
+        run: etc/bin/shellchecker
+
+      - name: MyPy
+        run: mypy
+
+      - name: Towncrier
+        run: towncrier build --draft
+
   codecov:
     needs: test
     runs-on: ubuntu-latest