chore: remove -rc2 tag in CMakeLists.txt VERSION field

Author: johnbartholomew

cpp/CMakeLists.txt

@@ -15,7 +15,7 @@ target_link_libraries(libjsonnet++ libjsonnet)
 # CMake prepends CMAKE_SHARED_LIBRARY_PREFIX to shared libraries, so without
 # this step the output would be |liblibjsonnet|.
 set_target_properties(libjsonnet++ PROPERTIES OUTPUT_NAME jsonnet++
-	VERSION     "0.21.0-rc2"
+	VERSION     "0.21.0"
 	SOVERSION   "0"
 	PUBLIC_HEADER "${LIB_HEADER}")
 install(TARGETS libjsonnet++