message: don't amend commits when cutting a new release
diff: @@ -80,7 +80,7 @@ file(STRINGS ${CMAKE_CURRENT_BINARY_DIR}/include/range/v3/version.hpp RANGE_V3_O
  file(STRINGS ${CMAKE_CURRENT_SOURCE_DIR}/include/range/v3/version.hpp RANGE_V3_NEW_VERSION_HPP)
  # If the new version.hpp is materially different from the one in the source
  -# directory, update it, amend the most recent commit, and tag the commit.
  +# directory, update it, commit, and tag.
  if(NOT RANGE_V3_NEW_VERSION_HPP STREQUAL RANGE_V3_OLD_VERSION_HPP)
  # Check that README.md and Version.cmake are the only changed file:
  execute_process(
  @@ -100,7 +100,7 @@ if(NOT RANGE_V3_NEW_VERSION_HPP STREQUAL RANGE_V3_OLD_VERSION_HPP)
  COMMAND ${GIT_EXECUTABLE} -C "${CMAKE_CURRENT_SOURCE_DIR}" add -u
  )
  execute_process(
  - COMMAND ${GIT_EXECUTABLE} -C "${CMAKE_CURRENT_SOURCE_DIR}" commit --amend --no-edit
  + COMMAND ${GIT_EXECUTABLE} -C "${CMAKE_CURRENT_SOURCE_DIR}" commit -m "${RANGE_V3_VERSION}"
  )
  execute_process(
  COMMAND ${GIT_EXECUTABLE} -C "${CMAKE_CURRENT_SOURCE_DIR}" tag -f -a "${RANGE_V3_VERSION}" -m "${RANGE_V3_VERSION}"
  