[7.9] [Jenkins] run CI when plugin readmes change (#74388) (#74413)

Co-authored-by: spalger <spalger@users.noreply.github.com>

Co-authored-by: spalger <spalger@users.noreply.github.com>

Author: Spencer

.ci/pipeline-library/src/test/prChanges.groovy

@@ -97,4 +97,17 @@ class PrChangesTest extends KibanaBasePipelineTest {
 
     assertFalse(prChanges.areChangesSkippable())
   }
+
+  @Test
+  void 'areChangesSkippable() with plugin readme changes'() {
+    props([
+      githubPrs: [
+        getChanges: { [
+          [filename: 'src/plugins/foo/README.asciidoc'],
+        ] },
+      ],
+    ])
+
+    assertFalse(prChanges.areChangesSkippable())
+  }
 }

vars/prChanges.groovy

@@ -22,6 +22,8 @@ def getNotSkippablePaths() {
   return [
     // this file is auto-generated and changes to it need to be validated with CI
     /^docs\/developer\/architecture\/code-exploration.asciidoc$/,
+    // don't skip CI on prs with changes to plugin readme files (?i) is for case-insensitive matching
+    /(?i)\/plugins\/[^\/]+\/readme\.(md|asciidoc)$/,
   ]
 }