Pinned event : create the feature flag

Author: ganfra

libraries/featureflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlags.kt

@@ -120,4 +120,11 @@ enum class FeatureFlags(
         defaultValue = { it.buildType != BuildType.RELEASE },
         isFinished = false,
     ),
+    PinnedEvents(
+        key = "feature.pinnedEvents",
+        title = "Pinned Events",
+        description = "Allow user to pin events in a room",
+        defaultValue = { false },
+        isFinished = false,
+    )
 }