source-book-ids metadata affected on reimport

[Dieterbe]

just upgraded the plugin to 1.16.6 and decided to re-import all my kindle clippings to confirm the fix for #26 after the re-import, running a git diff shows no change in authors pages, but it does show a diff like the below, one for every singe book. it looks like the the source-book-ids field somehow got messed up.

diff --git a/pages/highlights%2Fbook%2FAbundance%3A The Future Is Better Than You Think.md b/pages/highlights%2Fbook%2FAbundance%3A The Future Is Better Than You Think.md                                           
index a283b65..0197e5e 100644                                                                                                                                                                                        
--- a/pages/highlights%2Fbook%2FAbundance%3A The Future Is Better Than You Think.md                                                                                                                                  
+++ b/pages/highlights%2Fbook%2FAbundance%3A The Future Is Better Than You Think.md                                                                                                                                  
@@ -1,9 +1,9 @@                                                                                                                                                                                                      
 type:: Book
-last_sync:: 2022-08-19T06:00:10.749Z                                                                                                                                                                                
+last_sync:: 2022-08-20T17:59:47.115Z                                                                                                                                                                                
 author:: Diamandis, Peter H.;Kotler, Steven
 alias:: Abundance - Highlights
 title:: highlights/book/Abundance: The Future Is Better Than You Think
-source-book-ids:: c09ed53e1147551a70d5e4de53802532100ac485f3914c5be09f5f85                                                                                                                                          
+source-book-ids:: c,0,9,e,d,5,3,e,1,1,4,7,5,5,1,a,7,0,d,5,e,4,d,e,5,3,8,0,2,5,3,2,1,0,0,a,c,4,8,5,f,3,9,1,4,c,5,b,e,0,9,f,5,f,8,5,28c432845df7230962345a2f69705cac1f29621c17a2fff060e6b6b3   

[github-actions[bot]]

:tada: This issue has been resolved in version 1.16.7 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket:

[theBenForce]

@Dieterbe, I used the values that you supplied to write a unit test for book ID generation. Should be working now!