Generate new tables/variables for ISMIP6

[durack1]

Fix #107

[geresie]

Can you please add this model below to the 'input4MIPs_CV.json'?

"UKESM1-CM6-ssp585-1-0":{
"comment":"Prepared using CMIP6 model UKESM1-CM6 as input. A combination of historical and ssp585 datasets were used to create this ISMIP6 forcing dataset",
"contact":"ISMIP6 Steering Team ([email protected])",
"dataset_category":"surfaceFluxes",
"further_info_url":"http://www.climate-cryosphere.org/wiki/index.php?title=ISMIP6_wiki_page",
"institution":"NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA",
"institution_id":"NASA-GSFC",
"nominal_resolution":"10 km",
"product":"derived",
"references":"Experimental protocol for sealevel projections from ISMIP6 standalone ice sheet models, Nowicki, S. et al, 2020, https://doi.org/10.5194/tc-2019-322",
"release_year":"2020",
"source":"UKESM1-CM6-ssp585-1-0 derived dataset computed from CMIP6 UKESM1-CM6 historical and ssp585 simulations for ISMIP6",
"source_description":"Ice sheet relevant datasets produced by the ISMIP6 Team for the standalone ice sheet experiment of ISMIP6",
"source_id":"UKESM1-CM6-ssp585-1-0",
"source_type":"AOGCM",
"source_variables":[
"acabf",
"evspsbl",
"mrros",
"pr",
"sftflf",
"so",
"ts"
],
"source_version":"1.0",
"target_mip":"ISMIP6",
"title":"ISMIP6 (CMIP6) - UKESM1-CM6-ssp585-1-0 derived data prepared for input4MIPs"
}

Thanks so much!