Unify firmware version format with release builds.

examples/simple_repeater/MyMesh.h

@@ -112,11 +112,11 @@ struct NeighbourInfo {
 };
 
 #ifndef FIRMWARE_BUILD_DATE
-  #define FIRMWARE_BUILD_DATE   "19 Apr 2026"
+  #define FIRMWARE_BUILD_DATE   "Unspecified"
 #endif
 
 #ifndef FIRMWARE_VERSION
-  #define FIRMWARE_VERSION   "v1.15.0"
+  #define FIRMWARE_VERSION   "v1.15.0-vbart-meshcoretel"
 #endif
 
 #define FIRMWARE_ROLE "repeater"