update docs

.gitlab-ci.yml

 # This is a demo for integrating pylint results into GitLab. For more information see:
-# related Bits and Bytes article: [TODO: **BnB link**]
+# related Bits and Bytes article: https://docs.mpcdf.mpg.de/bnb/213.html
 # GitLab documentation          : https://docs.gitlab.com/ee/ci/testing/code_quality.html
 #
 # pylint        (python linter)                          : https://pylint.org
@@ -23,7 +23,7 @@ pylint:
       codequality: codeclimate.json
     when: always
   tags:
-    # run this job only on the runners with distributed cache
+    # as we're caching the installed python packages, we must run this job only on the runners with distributed cache
     - distributedcache
   cache:
     when: always

README.md

@@ -2,5 +2,5 @@
 
 Pylint-GitLab integration demo repository. Checkout the [accompanying Bits & Bytes article](https://docs.mpcdf.mpg.de/bnb/213.html).
 
-See [GitLab CI configuration](https://gitlab.mpcdf.mpg.de/mpcdf/training/pylint/-/blob/main/.gitlab-ci.yml) for integration details. Changes in the Pylint output can be inspected in each [merge request](https://gitlab.mpcdf.mpg.de/mpcdf/training/pylint/-/merge_requests/1). 
+See [GitLab CI configuration](https://gitlab.mpcdf.mpg.de/mpcdf/training/pylint/-/blob/main/.gitlab-ci.yml) for integration details. Changes in the Pylint output can be inspected in each [merge request](https://gitlab.mpcdf.mpg.de/mpcdf/training/pylint/-/merge_requests/2).