Added updated requirements.txt for Read the Docs builds (HTCONDOR-571)
Added updated requirements.txt for Read the Docs builds (HTCONDOR-571)

htcondor/htcondor,htcondor/htcondor,htcondor/htcondor,htcondor/htcondor,htcondor/htcondor,htcondor/htcondor,htcondor/htcondor,htcondor/htcondor