cmake: Update library and target names for qrcodegen

qrcodegen is identified as such (without the "lib" prefix) and as the
target "qrcodegencpp::qrcodegencpp" by the CMake package generated by
obs-deps.

CMakeLists.txt

@@ -18,7 +18,9 @@ find_qt(COMPONENTS Core Widgets Svg Network)
 find_package(nlohmann_json 3 REQUIRED)
 
 # Find qrcodegencpp
-find_package(Libqrcodegencpp REQUIRED)
+set(CMAKE_FIND_PACKAGE_PREFER_CONFIG ON)
+find_package(qrcodegencpp REQUIRED)
+set(CMAKE_FIND_PACKAGE_PREFER_CONFIG OFF)
 
 # Find WebSocket++
 find_package(Websocketpp 0.8 REQUIRED)
@@ -151,7 +153,7 @@ target_link_libraries(
           nlohmann_json::nlohmann_json
           Websocketpp::Websocketpp
           Asio::Asio
-          Libqrcodegencpp::Libqrcodegencpp)
+          qrcodegencpp::qrcodegencpp)
 
 set_target_properties_obs(
   obs-websocket