Create changelog directory
Create changelog directory

Also creates a .gitkeep file to enable git tracking the directory

Signed-off-by: Christian Kampka <2314b2e3a4a1f7db165be2aafbf1efd78f28cc97@kampka.net>

matrix-org/matrix-appservice-slack,matrix-org/matrix-appservice-slack,matrix-org/matrix-appservice-slack,matrix-org/matrix-appservice-slack