Remove release-note block indentation in PR template 🌮

Having the indentation on those code block make its more painful for
users to easily write the release note block.

Signed-off-by: Vincent Demeester <vdemeest@redhat.com>

.github/pull_request_template.md

@@ -28,19 +28,19 @@ release notes for the next release!
 
 For pull requests with a release note:
 
-    ```release-note
-    Your release note here
-    ```
+```release-note
+Your release note here
+```
 
 For pull requests that require additional action from users switching to the new release, include the string "action required" (case insensitive) in the release note:
 
-    ```release-note
-    action required: your release note here
-    ```
+```release-note
+action required: your release note here
+```
 
 For pull requests that don't need to be mentioned at release time, use the `/release-note-none` Prow command to add the `release-note-none` label to the PR. You can also write the string "NONE" as a release note in your PR description:
 
-    ```release-note
-    NONE
-    ```
+```release-note
+NONE
+```
 -->