Add missing includes for libc++

In file included from ../src/modules/custom.cpp:1:
In file included from ../include/modules/custom.hpp:7:
../include/util/command.hpp:15:25: error: implicit instantiation of undefined template 'std::__1::array<char, 128>'
  std::array<char, 128> buffer = {0};
                        ^
../src/modules/pulseaudio.cpp:175:41: error: implicit instantiation of undefined template 'std::__1::array<std::__1::basic_string<char>, 9>'
static const std::array<std::string, 9> ports = {
                                        ^
/usr/include/c++/v1/__tuple:223:64: note: template is declared here
template <class _Tp, size_t _Size> struct _LIBCPP_TEMPLATE_VIS array;
                                                               ^
In file included from ../src/factory.cpp:1:
In file included from ../include/factory.hpp:8:
../include/modules/sway/workspaces.hpp:39:8: error: no template named 'unordered_map' in namespace 'std'
  std::unordered_map<std::string, Gtk::Button> buttons_;
  ~~~~~^
../src/factory.cpp:20:14: error: cannot initialize return object of type 'waybar::AModule *' with an rvalue of type 'waybar::modules::sway::Workspaces *'
      return new waybar::modules::sway::Workspaces(id, bar_, config_[name]);
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

include/util/command.hpp

@@ -3,6 +3,7 @@
 #include <giomm.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <array>
 
 namespace waybar::util::command {