Upgrade version to 0.11.1 (#246)

A minor new version. Mostly for packaging the library in Release mode.

cmake/ftxui_git_version.cmake

@@ -1,13 +0,0 @@
-find_package(Git QUIET)
-if (Git_FOUND AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git")
-  message("git found")
-  execute_process(
-    COMMAND ${GIT_EXECUTABLE} rev-list --count HEAD
-    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-    OUTPUT_VARIABLE git_version
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-  )
-else()
-  set(git_version 0)
-endif()
-