Release metadig-engine v.2.3.3

[gothub]

• [x] close all issues for this release
• [x] run unit tests
• [x] test build on dev k8s cluster
• [x] update docker tag to 2.3.3
• [x] build all docker images
• [x] push docker images to docker hub
• [x] merge dev branch into master
• [x] create release tag: https://github.com/NCEAS/metadig-engine/tree/v2.3.3
• [x] update image revision in all production k8s manifest files