release-steps.txt: simplify ImgLib2 release steps
release-steps.txt: simplify ImgLib2 release steps

This simplification is possible thanks to the script we now have for
tagging an ImgLib release.

biovoxxel/imagej,TehSAUCE/imagej,TehSAUCE/imagej,TehSAUCE/imagej,biovoxxel/imagej,biovoxxel/imagej