Are there instructions for how to build a docker container for an unreleased version of Apache Flink (e.g. 1.17.1)? I'm trying to build and containerize 1.17.1 from source and would appreciate being pointed in the right direction

You should be able to start with the Dockerfile for 1.17.0 (here: https://github.com/apache/flink-docker/blob/1cb66d334bd1a1a9a7627c47478a31afed542aab/1.17/scala_2.12-java11-ubuntu/Dockerfile) and change the download URLs at lines 47-48 to get the version that you want.