removing unneeded package from manifest that is outdated (#172)

PerformanceTests/UnityPerformanceBenchmark-LWRP/Packages/manifest.json

@@ -9,7 +9,6 @@
     "com.unity.shadergraph": "6.5.3",
     "com.unity.test-framework": "1.0.14",
     "com.unity.textmeshpro": "2.0.1",
-    "com.unity.timeline": "1.1.0",
     "com.unity.xr.legacyinputhelpers": "2.0.4",
     "com.unity.modules.ai": "1.0.0",
     "com.unity.modules.androidjni": "1.0.0",