Add 5 pipeline values (#9344)

* Update pipeline-values.adoc

* Update pipeline-values.adoc

* Update pipeline-values.adoc

* Update pipeline-values.adoc

Author: BeFunes

Diff for: jekyll/_includes/partials/pipelines-and-triggers/pipeline-values.adoc

@@ -387,4 +387,39 @@ a|  * GitLab: push, merge request
 | icon:check[]
 | icon:times[]
 
+| `pipeline.event.github.pull_request.base.ref`
+| GitHub App
+| String
+| The name of the *base* (or target) branch of the PR - that is the branch that will receive the changes. Only populated for pipelines triggered xref:github-trigger-event-options/#supported-trigger-options[by pull request events] (`pipeline.event.name = 'pull_request'`). 
+| icon:check[]
+| icon:times[]
+
+| `pipeline.event.github.pull_request.head.ref`
+| GitHub App
+| String
+| The name of the *head* branch of the PR - that is the branch containing the changes to be merged. Only populated for pipelines triggered xref:github-trigger-event-options/#supported-trigger-options[by pull request events] (`pipeline.event.name = "pull_request"`). 
+| icon:check[]
+| icon:times[]
+
+| `pipeline.event.github.pull_request.draft`
+| GitHub App
+| Boolean
+| A boolean value indicating whether the pull request is a draft. Only populated for pipelines triggered xref:github-trigger-event-options/#supported-trigger-options[by pull request events] (`pipeline.event.name = "pull_request"`). 
+| icon:check[]
+| icon:times[]
+
+| `pipeline.event.github.pull_request.title`
+| GitHub App
+| String
+| The title of the pull request. Only populated for pipelines triggered xref:github-trigger-event-options/#supported-trigger-options[by pull request events] (`pipeline.event.name = "pull_request"`). 
+| icon:check[]
+| icon:times[]
+
+| `pipeline.event.github.pull_request.number`
+| GitHub App
+| Integer
+| The numeric identifier of the pull request. Only populated for pipelines triggered xref:github-trigger-event-options/#supported-trigger-options[by pull request events] (`pipeline.event.name = "pull_request"`). 
+| icon:check[]
+| icon:times[]
+
 |===