docs: list the libgdx lab

README.md

@@ -15,6 +15,7 @@ deliberately no parent aggregator POM, so every lab stays standalone.
 | [netty/](netty/) | `try-netty` | Netty 4 channel handlers (JSON / FlatBuffers packets) |
 | [resilience4j/](resilience4j/) | `try-resilience4j` | Resilience4j fault-tolerance demo |
 | [discord4j/](discord4j/) | `try-discord4j` | Discord4J bot starter |
+| [libgdx/](libgdx/) | `libGDX-tutorial` | libGDX game framework — desktop, Android and HTML targets |
 | [maven/](maven/) | `maven-copy-dependencies-example` | maven-dependency-plugin: copy dependencies into `lib/` |
 | [micrometer/](micrometer/) | `try-micrometer` | Micrometer metrics shipped into ELK |
 | [elk/](elk/) | `try-elk` | Logging with the ELK stack |