Add chmod on start

Etcd 3.4.9 introduced a check on the data directory permissions that
require 0700. Since this causes the server to not come up we will
attempt to change the perms.

Update etcd to 3.4.9

This also ends up setting the data dir to 0700 to satisfy a new check
added to the data dir. #41 requested this changed for security reasons
and it was denied, but must ultimately be changed to maintain
compatibility with etcd.

Update .drone.yml

Add table encryption

Update README.md

Implement default s3 path when only bucket provided for etcd snapshots (

#37)

* Implement default s3 path when only bucket provided for etcd snapshots

* Test default snapshot path and explicit snapshot path

Ensure tag belongs to EC2 instance

Update package build

Add additional version info

Fix linting issue