Improve _invalid_sequential_version msg. (#533)

* Improved `_invalid_sequential_version` msg.

* replace 'recommended' by 'required'.

* Update src/AutoMerge/guidelines.jl

* Update src/AutoMerge/guidelines.jl

---------

Co-authored-by: Eric Hanson <[email protected]>

Author: shayandavoodii

src/AutoMerge/guidelines.jl

@@ -424,7 +424,7 @@ function meets_repo_url_requirement(pkg::String; registry_head::String)
 end
 
 function _invalid_sequential_version(reason::AbstractString)
-    return false, "Does not meet sequential version number guideline: $reason", :invalid
+    return false, "Does not meet sequential version number guideline: $(reason). If this was intentional, please leave a comment saying so. Otherwise please correct the version number in your package and re-trigger registration.", :invalid
 end
 
 function _valid_change(old_version::VersionNumber, new_version::VersionNumber)