Caproto API break for nslsii.iocs.thermo_sim

[mrakitin]

An attempt to build nslsii v0.2.0 with conda (see conda-forge/nslsii-feedstock#4) resulted in the following error:

import: 'nslsii.iocs.thermo_sim'
Traceback (most recent call last):
  File "/home/conda/feedstock_root/build_artifacts/nslsii_1629837377820/test_tmp/run_test.py", line 50, in <module>
    import nslsii.iocs.thermo_sim
  File "/home/conda/feedstock_root/build_artifacts/nslsii_1629837377820/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/nslsii/iocs/thermo_sim.py", line 8, in <module>
    class Thermo(PVGroup):
  File "/home/conda/feedstock_root/build_artifacts/nslsii_1629837377820/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/nslsii/iocs/thermo_sim.py", line 44, in Thermo
    @readback.scan(period=.1, use_scan_field=True)
  File "/home/conda/feedstock_root/build_artifacts/nslsii_1629837377820/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/caproto/server/server.py", line 1028, in scan
    '`use_scan_field=True` requires `record="..."` to be set'
caproto._utils.CaprotoValueError: `use_scan_field=True` requires `record="..."` to be set

Looks like the API of caproto has changed. I am going to skip that exact test, but we need to fix it in the next release.