Update workspace directory for windows pull request job

.ci/jobs.t/elastic+elasticsearch+pull-request+part-3-windows.yml

@@ -4,7 +4,7 @@
     display-name: "elastic / elasticsearch - pull request part-3 windows"
     description: "Testing of Elasticsearch pull requests - part-3 windows"
     node: "windows-immutable"
-    workspace: "C:\\Users\\jenkins\\workspace\\pr-part-2\\${BUILD_NUMBER}"
+    workspace: "C:\\Users\\jenkins\\workspace\\pr-part-3-windows\\${BUILD_NUMBER}"
     scm:
       - git:
           refspec: "+refs/pull/${ghprbPullId}/*:refs/remotes/origin/pr/${ghprbPullId}/*"