Fix wrong indentation in gitlab issue template

To put text into gray box the text need to be prepended by four spaces.

.gitlab/issue_templates/blog-post.md

@@ -9,14 +9,15 @@
     If you know their GitLab aliases, use @username to keep them 
     involved.
 
-## Reviewer
+## Reviewers
 
     Who do you want as reviewers of your Blog Post?
 
 ## Topic and Content
 
     Outline what you want to write about.
-    Specify the style of your post (e.g. report, user story, guide… ).
+    Specify the style of your post (e.g. report, user story, guide, 
+    etc.).
 
 ## Target Audience
 
@@ -29,5 +30,5 @@
 
 ## Contribution
 
-   How does the content of your Blog Post contribute to the goals of
-   HIFIS Software-Services?
+    How does the content of your Blog Post contribute to the goals of
+    HIFIS Software-Services?