Add 'BuildRequires: abseil-cpp-devel' when building with libphonenumber

The libphonenumber depends on it, due to a header from that package
being included in a public libphonenumber header, but libphonenumber's
devel subpackage does not require it, thus add it here for now.

evolution-data-server.spec

@@ -122,6 +122,7 @@ BuildRequires: krb5-devel >= 1.11
 BuildRequires: libphonenumber-devel
 BuildRequires: protobuf-devel
 BuildRequires: boost-devel
+BuildRequires: abseil-cpp-devel
 %endif
 
 %description