We're facing a case where we would like to use 0.5 CPU for a task, it would be great to replace the type of `cpuCores` by `Double` instead of `Long`: https://github.com/elixir-cloud-aai/tesk-api/blob/c4494e5066b176544e138023f5d04663ea7a5c3d/src/main/java/uk/ac/ebi/tsc/tesk/tes/model/TesResources.java#L18