Add info to ui-showcase project

dokka-integration-tests/gradle/projects/ui-showcase/README.md

@@ -5,9 +5,21 @@ This is a Dokka test project for UI e2e tests.
 The goal is to have as much variety of UI elements in one project as possible, so that during refactorings
 we can compare the outputs between different versions of Dokka and make sure we didn't break any corner cases.
 
-### Run from root of the project
+### Run from the root of the project
 
 ```bash
 export DOKKA_TEST_OUTPUT_PATH="build/ui-showcase-result"
 ./gradlew :dokka-integration-tests:gradle:testUiShowcaseProject
 ```
+
+### Run with the published Dokka version
+
+Dokka should be published in one of the following repositories:
+[MavenCentral](https://central.sonatype.com),
+[dev](https://maven.pkg.jetbrains.space/kotlin/p/dokka/dev) or
+[test](https://maven.pkg.jetbrains.space/kotlin/p/dokka/test)
+
+```bash
+export DOKKA_TEST_OUTPUT_PATH="build/ui-showcase-result"
+./gradlew :dokka-integration-tests:gradle:testUiShowcaseProject -Porg.jetbrains.dokka.integration_test.dokkaVersionOverride=2.0.0-dev-329
+```