Add ipynb format check (#1439)

* Update test_qlib_from_source.yml

* add ipynb format check to workflow

* test ipynb CI

* modify nbqa check path

* add pylint flake8 mypy check to ipynb

* check ipynb with black and pylint

* reformat .ipynb files

* format line length

nbqa black . -l 120

* update nbqa .ipynb format CI

* format old ipynb files

* add nbconvert check to CI

* adjust CI order to avoid repeating download data

.github/workflows/test_qlib_from_source.yml

@@ -121,6 +121,11 @@ jobs:
       run: |
         mypy qlib --install-types --non-interactive || true
         mypy qlib --verbose
+    
+    - name: Check Qlib ipynb with nbqa
+      run: |
+        nbqa black . -l 120 --check --diff
+        nbqa pylint . --disable=C0104,C0114,C0115,C0116,C0301,C0302,C0411,C0413,C1802,R0401,R0801,R0902,R0903,R0911,R0912,R0913,R0914,R0915,R1720,W0105,W0123,W0201,W0511,W0613,W1113,W1514,E0401,E1121,C0103,C0209,R0402,R1705,R1710,R1725,R1735,W0102,W0212,W0221,W0223,W0231,W0237,W0612,W0621,W0622,W0703,W1309,E1102,E1136,W0719,W0104,W0404,C0412,W0611,C0410 --const-rgx='[a-z_][a-z0-9_]{2,30}$'
 
     - name: Test data downloads
       run: |
@@ -139,6 +144,12 @@ jobs:
         brew unlink libomp
         brew install libomp.rb
 
+    # Run after data downloads
+    - name: Check Qlib ipynb with nbconvert
+      run: |
+        # add more ipynb files in future
+        jupyter nbconvert --to notebook --execute examples/workflow_by_code.ipynb
+
     - name: Test workflow by config (install from source)
       run: |
         python -m pip install numba