Update changelog for Docker Improvements

Docker improvement

Dockerfile.dev is ignored by both git and docker for faster development
cycle of docker build.

Update Dockefile to get a much smaller footprint with alpine image.

Optimize ordering of build steps to avoid needless downloads.

Include CA certificates needed for practical use.

Update Makefile to build a static binary by default.

build: use go 1.11

Release 3.0.0

Migration from Bitly to Pusher