PROTON-1944: update .so version to account for changes
diff --git a/cpp/versions.cmake b/cpp/versions.cmake
index d05ecce..dac6ee6 100644
--- a/cpp/versions.cmake
+++ b/cpp/versions.cmake
@@ -1,4 +1,4 @@
 set(PN_LIB_CPP_MAJOR_VERSION 12)
-set(PN_LIB_CPP_MINOR_VERSION 3)
+set(PN_LIB_CPP_MINOR_VERSION 4)
 set(PN_LIB_CPP_PATCH_VERSION 0)
 set(PN_LIB_CPP_VERSION "${PN_LIB_CPP_MAJOR_VERSION}.${PN_LIB_CPP_MINOR_VERSION}.${PN_LIB_CPP_PATCH_VERSION}")