Ignore checking the doc8 format on build and _build directories

Signed-off-by: Chin Yeung Li <tli@nexb.com>

Author: chinyeungli

.github/workflows/docs-ci.yml

@@ -27,6 +27,6 @@ jobs:
         run: make docs-check
 
       - name: Check documentation for style errors
-        run: make doc8
+        run: make doc8 --ignore-path docs/build,docs/_build