message: [cmake] Fix regex escaping in Version.cmake
  According to [1], string literals in CMake cannot contain '\', they need
  to be escaped. Therefore, if we want to pass '\' to string(REGEX), we
  need to use '\\'.
  [1]: <https://cmake.org/cmake/help/latest/manual/cmake-language.7.html#quoted-argument>
diff: @@ -32,7 +32,7 @@ function(GetVersionInformation VersionTripleVar VersionStringVar)
  OUTPUT_VARIABLE git_branch
  WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
  OUTPUT_STRIP_TRAILING_WHITESPACE)
  - string(REGEX MATCH "^(.*)\/(.*)$$" _ ${git_branch})
  + string(REGEX MATCH "^(.*)\\/(.*)$$" _ ${git_branch})
  set(THE_GIT_BRANCH "${CMAKE_MATCH_2}")
  message(STATUS "[Version] Git branch: ${THE_GIT_BRANCH}")
  @@ -44,11 +44,11 @@ function(GetVersionInformation VersionTripleVar VersionStringVar)
  message(STATUS "[Version] Git SHA: ${THE_GIT_SHA_SHORT}")
  file(READ "${CMAKE_SOURCE_DIR}/Changelog.md" changelog_contents)
  - string(REGEX MATCH "^^### ([0-9]*\.[0-9]+\.[0-9]+).*$" _ "${changelog_contents}")
  + string(REGEX MATCH "^^### ([0-9]*\\.[0-9]+\\.[0-9]+).*$" _ "${changelog_contents}")
  # extract and construct version triple
  set(THE_VERSION ${CMAKE_MATCH_1})
  # extract suffix, construct full version string
  - string(REGEX MATCH "^^### ([0-9]*\.[0-9]+\.[0-9]+) \\(([^\)]*)\\).*$" _ "${changelog_contents}")
  + string(REGEX MATCH "^^### ([0-9]*\\.[0-9]+\\.[0-9]+) \\(([^\)]*)\\).*$" _ "${changelog_contents}")
  if(NOT ("${CMAKE_MATCH_2}" STREQUAL ""))
  set(THE_VERSION_STRING "${THE_VERSION}-${CMAKE_MATCH_2}-${THE_GIT_BRANCH}-${THE_GIT_SHA_SHORT}")
  @@ -61,10 +61,10 @@ function(GetVersionInformation VersionTripleVar VersionStringVar)
  if(("${THE_VERSION}" STREQUAL "" OR "${THE_VERSION_STRING}" STREQUAL "") AND (EXISTS "${CMAKE_SOURCE_DIR}/Changelog.md"))
  file(READ "${CMAKE_SOURCE_DIR}/Changelog.md" changelog_contents)
  # extract and construct version triple
  - string(REGEX MATCH "^^### ([0-9]*\.[0-9]+\.[0-9]+).*$" _ "${changelog_contents}")
  + string(REGEX MATCH "^^### ([0-9]*\\.[0-9]+\\.[0-9]+).*$" _ "${changelog_contents}")
  set(THE_VERSION ${CMAKE_MATCH_1})
  # extract suffix, construct full version string
  - string(REGEX MATCH "^^### ([0-9]*\.[0-9]+\.[0-9]+) \\(([^\)]*)\\).*$" _ "${changelog_contents}")
  + string(REGEX MATCH "^^### ([0-9]*\\.[0-9]+\\.[0-9]+) \\(([^\)]*)\\).*$" _ "${changelog_contents}")
  if(NOT ("${CMAKE_MATCH_2}" STREQUAL ""))
  set(THE_VERSION_STRING "${THE_VERSION}-${CMAKE_MATCH_2}")
  else()
  