Improve tags warning

CMake/VTKDetermineVersion.cmake

@@ -63,10 +63,18 @@ function(determine_version source_dir git_command var_prefix)
           NOT tmp_MINOR_VERSION STREQUAL ${var_prefix}_MINOR_VERSION)
         message(WARNING
           "Version from git (${tmp_VERSION}) disagrees with hard coded version (${${var_prefix}_VERSION}). Either update the git tags or version.txt.")
+        if (NOT "$ENV{CI}" STREQUAL "")
+          message(WARNING
+            "Please update your fork tags, using this command: `git fetch origin --tags && git push gitlab --tags`.")
+        endif ()
       endif ()
     elseif (NOT "${tmp_VERSION}" STREQUAL "${${var_prefix}_VERSION}")
       message(WARNING
         "Version from git (${tmp_VERSION}) disagrees with hard coded version (${${var_prefix}_VERSION}). Either update the git tags or version.txt.")
+      if (NOT "$ENV{CI}" STREQUAL "")
+        message(WARNING
+          "Please update your fork tags, using this command: `git fetch origin --tags && git push gitlab --tags`.")
+      endif ()
     endif()
     foreach(suffix VERSION VERSION_MAJOR VERSION_MINOR VERSION_PATCH
                    VERSION_PATCH_EXTRA VERSION_FULL VERSION_IS_RELEASE)