CMake: Require qt>=5.7

CMake/generate.conf

@@ -38,12 +38,12 @@ find: Threads REQUIRED
 [CMake:Deps:Qt5Widgets]
 link: Qt5::Widgets
 include: ${Qt5Widgets_INCLUDE_DIRS}
-find: Qt5 REQUIRED COMPONENTS Core Widgets
+find: Qt5 5.7 REQUIRED COMPONENTS Core Widgets
 [CMake:Deps:Qt5Xml]
 link: Qt5::Xml
 include:${Qt5Xml_INCLUDE_DIRS}
-find: Qt5 REQUIRED COMPONENTS Core Xml
+find: Qt5 5.7 REQUIRED COMPONENTS Core Xml
 [CMake:Deps:graphviz]
 link: ${GRAPHVIZ_GVC_LIBRARY} ${GRAPHVIZ_CGRAPH_LIBRARY}
@@ -58,4 +58,4 @@ find: jsoncpp REQUIRED
 [CMake:Deps:readline]
 link: ${Readline_LIBRARY}
 include: ${Readline_INCLUDE_DIR}
-find: readline REQUIRED
\ No newline at end of file
+find: readline REQUIRED