Improve lint job to check only python scripts

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>

debian/apertis/local-pre-source-build-gitlab-ci.yml

@@ -3,17 +3,26 @@ lint:
   image: debian:bookworm-slim
   tags:
     - lightweight
-  variables:
-    FILES: tools/
-  script:
+  before_script:
     - apt update
     - apt install --no-install-recommends -y
         black
         flake8
         isort
-    - isort $FILES --check-only --diff
-    - black $FILES --check --diff
-    - flake8 $FILES
+  script:
+    - TOOLS=$(find tools/ -type f | sort)
+    - |
+      for SCRIPT in $TOOLS
+      do
+        GREP_PYTHON=$(grep '^#!/usr/bin/.*python' $SCRIPT || true)
+        if [ ! -z "$GREP_PYTHON" ]
+        then
+          PYTHON_SCRIPTS="$PYTHON_SCRIPTS $SCRIPT"
+        fi
+      done
+    - isort --profile black $PYTHON_SCRIPTS --check-only --diff
+    - black $PYTHON_SCRIPTS --check --diff
+    - flake8 $PYTHON_SCRIPTS
   needs:
     - pipeline: $PARENT_PIPELINE_ID
       job: prepare-build-env