Fix image in docs

DevOps Report instead of DevOps Score
Plus adjust the issue_workflow.md

doc/development/contributing/issue_workflow.md

@@ -190,7 +190,7 @@ their color is `#428BCA`.
 
 For instance, the "DevOps Report" category is represented by the
 ~"Category:DevOps Reports" label in the `gitlab-org` group since its
-`devops_score.name` value is "DevOps Reports".
+`devops_reports.name` value is "DevOps Reports".
 
 If a category's label doesn't respect this naming convention, it should be specified
 with [the `label` attribute](https://about.gitlab.com/handbook/marketing/website/#category-attributes)

doc/user/admin_area/analytics/user_cohorts.md

@@ -10,7 +10,7 @@ GitLab lets you analyze the users' activities over time of your GitLab installat
 How do we read the user cohorts table? Let's take an example with the following
 user cohorts.
 
-![User cohort example](img/cohorts.png)
+![User cohort example](img/cohorts_v13_4.png)
 
 For the cohort of March 2020, three users have been added on this server and have
 been active since this month. One month later, in April 2020, two users are