Although this package is not a "-dev" package, it installs a "libsomething.so" symbolic link referencing the corresponding shared library. When the link doesn't include the version number, it is used by the linker when other programs are built against this shared library.
Shared libraries are supposed to place such symbolic links in their respective "-dev" packages, so it is a bug to include it with the main library package.
However, if this is a small package which includes the runtime and the development libraries, this is not a bug. In the latter case, please override this warning.