Git commits in Moodle 3.8.x by John Yao

commit b423c5ad383edc39314bab2b0a2229461a36aa8c
Author: John Yao <johnyao@catalyst-au.net>
Date:   Mon, 16 Dec 2019 08:28:04 +0800
Tag:    v3.8.1

MDL-67524 book: fixing view hidden chapter issue

commit 96e444665e46d0756fc7aa291df38d134a938439
Author: John Yao <johnyao@catalyst-au.net>
Date:   Thu, 04 Jul 2019 13:52:26 +0800
Tag:    v3.8.0-beta

MDL-65517 block_timeline: Hide completed course modules in Timeline

commit 62f1640df2b5a9ecd9631ca46bb6f24e2be3c2ba
Author: John Yao <johnyao@catalyst-au.net>
Date:   Mon, 17 Jun 2019 12:04:04 +0800
Tag:    v3.8.0-beta

MDL-65116 mod_assign : Assignment due date does not update for groups.