databases/mongodb36: update 3.6.18 -> 3.6.19

• Update conflicts: 3.4 is gone, 4.4 is new

PR: 248505
Submitted by: Ronald Klop <ronald-lists@klop.ws>
Approved by: dev@dudu.ro (maintainer)
Relnotes: https://docs.mongodb.com/v3.6/release-notes/3.6/#july-23-2020