book: update nl

Updated via the `update-book.yml` GitHub workflow.

Author: ttaylorr

external/book/content/book/nl/v2/_index.html

@@ -8,7 +8,7 @@
   language_code: nl
   front_page: true
   repository_url: https://github.com/progit/progit2-nl
-  sha: 568f5f550f2a8a69e48cc92d19df613ab9320864
+  sha: 645e0964a182f7da92075620ccf737e127e92224
   ebook_pdf: https://github.com/progit/progit2-nl/releases/download/2.1.117/progit.pdf
   ebook_epub: https://github.com/progit/progit2-nl/releases/download/2.1.117/progit.epub
 page_title: Git - Book

external/book/sync/book-nl.sha

@@ -1 +1 @@
-568f5f550f2a8a69e48cc92d19df613ab9320864
+645e0964a182f7da92075620ccf737e127e92224