pin ruamel.yaml to working version
pin ruamel.yaml to working version

SciDAP/cwltool,common-workflow-language/cwltool,dleehr/cwltool,dleehr/cwltool,SciDAP/cwltool,dleehr/cwltool,common-workflow-language/cwltool,SciDAP/cwltool,chapmanb/cwltool,jeremiahsavage/cwltool,common-workflow-language/cwltool,SciDAP/cwltool,chapmanb/cwltool,dleehr/cwltool,jeremiahsavage/cwltool,chapmanb/cwltool,jeremiahsavage/cwltool,chapmanb/cwltool,jeremiahsavage/cwltool