meson: Add boost to the dependencies

Since the project uses boost library add it to meson dependencies.

Tested:
Local build no longer fails with a missing boost headers message on the
system without boost, but fails at the "meson setup build" stage with
an appropriate message.

Change-Id: I872159dcec923d289626b532146c9eb8d5461e1c
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
diff --git a/phosphor-ldap-config/meson.build b/phosphor-ldap-config/meson.build
index 925ff8d..24060ea 100644
--- a/phosphor-ldap-config/meson.build
+++ b/phosphor-ldap-config/meson.build
@@ -1,6 +1,7 @@
 ldap_dep = meson.get_compiler('cpp').find_library('ldap', required: true)
 
 phosphor_ldap_conf_deps = [
+    boost_dep,
     cereal_dep,
     phosphor_dbus_interfaces_dep,
     phosphor_logging_dep,