more build deps for kactivities-workspace

kactivitymanagerd.spec

@@ -52,6 +52,9 @@ Requires: kactivities-workspace = %{version}-%{release}
 ## TEMPORARY, will (should-be) Obsoletes/Provides'd by plasma-desktop-5.6.x
 %package -n kactivities-workspace
 Summary: Kactivities workspace components
+BuildRequires: cmake(KF5Activities)
+BuildRequires: cmake(KF5Declarative)
+BuildRequires: cmake(KF5KCMUtils)
 # upgrade path
 Obsoletes: kf5-kactivities < 5.21.0
 Requires: %{name} = %{version}-%{release}