[Dockerfile uses 2.14](https://github.com/wurmlab/sequenceserver/blob/master/Dockerfile#L3) while [GH actions use 2.12](https://github.com/wurmlab/sequenceserver/blob/a9a128b9d8db327c015c8a552b0c3b9c6831a283/.github/workflows/tests.yml#L37-L39), update so that both consistently use the latest version