New command: qmk lint (#10761)

* Basic qmk lint command

* check for keymap readme

* change the workflow from qmk info to qmk lint

* add a strict mode

* parsing -> parse

* document qmk lint

* small info logging cleanup

* Apply suggestions from code review

Co-authored-by: Ryan <fauxpark@gmail.com>

* honor --strict in more places

* change the job name to lint

Co-authored-by: Ryan <fauxpark@gmail.com>

.github/workflows/lint.yml

@@ -0,0 +1,51 @@
+name: PR Lint keyboards
+
+on:
+  pull_request:
+    paths:
+    - 'keyboards/**'
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    container: qmkfm/base_container
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+
+    - uses: trilom/file-changes-action@v1.2.4
+      id: file_changes
+      with:
+        output: '\n'
+
+    - name: Print info
+      run: |
+        git rev-parse --short HEAD
+        echo ${{ github.event.pull_request.base.sha }}
+        echo '${{ steps.file_changes.outputs.files}}'
+
+    - name: Run qmk lint
+      shell: 'bash {0}'
+      run: |
+        QMK_CHANGES=$(echo -e '${{ steps.file_changes.outputs.files}}')
+        QMK_KEYBOARDS=$(qmk list-keyboards)
+
+        exit_code=0
+        for KB in $QMK_KEYBOARDS; do
+          KEYBOARD_CHANGES=$(echo "$QMK_CHANGES" | grep -E '^(keyboards/'${KB}'/)')
+          if [[ -z "$KEYBOARD_CHANGES" ]]; then
+            # skip as no changes for this keyboard
+            continue
+          fi
+
+          KEYMAP_ONLY=$(echo "$KEYBOARD_CHANGES" | grep -cv /keymaps/)
+          if [[ $KEYMAP_ONLY -gt 0 ]]; then
+            echo "linting ${KB}"
+
+            qmk lint --keyboard ${KB}
+          fi
+        done
+        exit $exit_code