gnucash-docs master: Change CMakeLists.txt version back to 3.900

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/3191b329 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/48fc3eaa (commit)



commit 3191b32990cf6d51de1699d1747f9da561739ca5
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Mar 28 16:20:25 2020 -0700

    Change CMakeLists.txt version back to 3.900



Summary of changes:
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)