Reorder Issues and Integrating with the Gerrit Checks plugin sections

Issues moved above Plugin Releases, to make it easier to find.

"Integrating with the Gerrit Checks plugin" section moved to "Jenkins
Setup" from "Why a new name?".

Also fixed header level for Issues and Plugin Releases, it should be h2,
that is section title, not h1, that is page title.

Also changes some header levels

Author: whut

README.md

@@ -59,25 +59,6 @@ have their own Gerrit integration defined and working out-of-the-box.
 No more people asking "how do I configure the Gerrit integration"? it
 will just work.
 
-### Integrating with the Gerrit Checks plugin
-
-The [Gerrit Checks plugin](https://gerrit-review.googlesource.com/Documentation/config-plugins.html#checks)
-provides a different approach to integrate CI systems with Gerrit. The
-GerritCodeReview-plugin supports the usage of the checks plugin, making it even
-more convenient to integrate automated verification into the code review.
-
-To build changes with pending checks, create a new `Multibranch Pipeline` item
-and select `Branch Source` of type `Gerrit` as described above. Then add the
-`Filter by Pending Checks`-behaviour to the `Gerrit Branch Source`. To select
-checkers, which should be checked for whether their checks are pending, under
-`Query Operator` either select to query pending checks by checker scheme to
-select a whole group of checkers or by a specific checker UUID, to only query
-by a specific checker. In the `Query String`-field enter the scheme name or checker
-UUID respectively.
-
-Jenkins will then only start builds for changes that have pending checks handled
-by the configured checkers and will set the status of the check to `SCHEDULED`.
-
 ## Jenkins Setup
 
 ### Using Multibranch Pipeline
@@ -159,6 +140,25 @@ discovered and made available to the pipeline steps.
 For the pipeline projects (non-multibranch) the variables would need to be set through
 an external triggering job (e.g. Gerrit Trigger Plugin).
 
+### Integrating with the Gerrit Checks plugin
+
+The [Gerrit Checks plugin](https://gerrit-review.googlesource.com/Documentation/config-plugins.html#checks)
+provides a different approach to integrate CI systems with Gerrit. The
+GerritCodeReview-plugin supports the usage of the checks plugin, making it even
+more convenient to integrate automated verification into the code review.
+
+To build changes with pending checks, create a new `Multibranch Pipeline` item
+and select `Branch Source` of type `Gerrit` as described above. Then add the
+`Filter by Pending Checks`-behaviour to the `Gerrit Branch Source`. To select
+checkers, which should be checked for whether their checks are pending, under
+`Query Operator` either select to query pending checks by checker scheme to
+select a whole group of checkers or by a specific checker UUID, to only query
+by a specific checker. In the `Query String`-field enter the scheme name or checker
+UUID respectively.
+
+Jenkins will then only start builds for changes that have pending checks handled
+by the configured checkers and will set the status of the check to `SCHEDULED`.
+
 ## Jenkinsfile Steps
 
 Gerrit Code Review plugin provides steps for allowing to post the
@@ -248,7 +248,12 @@ node {
 }
 ```
 
-# Plugin Releases
+## Issues
+
+The issues are tracked on the [Jenkins Issues portal](https://issues.jenkins-ci.org/issues/?jql=project%20%3D%20JENKINS%20AND%20status%20in%20(Open%2C%20%22In%20Progress%22%2C%20Reopened)%20AND%20component%20%3D%20gerrit-code-review-plugin)
+under the `gerrit-code-review-plugin` component.
+
+## Plugin Releases
 
 I have presented the first prototype of this new plugin at the Jenkins
 World Conference in San Francisco back in 2017 inside my "Data-Driven
@@ -517,8 +522,3 @@ feedback.
 
 Support for BlueOcean, including change description, hyperlink and owner
 visible from Jenkins UI.
-
-# Issues
-
-The issues are tracked on the [Jenkins Issues portal](https://issues.jenkins-ci.org/issues/?jql=project%20%3D%20JENKINS%20AND%20status%20in%20(Open%2C%20%22In%20Progress%22%2C%20Reopened)%20AND%20component%20%3D%20gerrit-code-review-plugin)
-under the `gerrit-code-review-plugin` component.