FindLua: Add support for Lua 5.4

Currently Lua 5.4 won't be found:

CMake Error at /usr/share/cmake-3.17/Modules/FindPackageHandleStandardArgs.cmake:164 (message):
  Could NOT find Lua (missing: LUA_INCLUDE_DIR) (Required is at least version
  "5.3")
Call Stack (most recent call first):
  /usr/share/cmake-3.17/Modules/FindPackageHandleStandardArgs.cmake:445 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.17/Modules/FindLua.cmake:232 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:12 (find_package)

After the change it works as intended:

-- Found Lua: /usr/lib/liblua5.4.so;/usr/lib/libm.so (found suitable version "5.4.0", minimum required is "5.3")

Backport: release
Topic-rename: FindLua-5.4