Rounding required for °F temperature conversion in Napalm device status tab

[candlerb]

NetBox version

v3.0.2

Python version

3.8

Steps to Reproduce

1. Configure napalm
2. Go to a napalm-enabled device which reports temperature (mine's a Mikrotik RB4011)
3. Go to the Status tab: /dcim/devices/<N>/status/
4. Look at the °F temperature conversion

Expected Behavior

°F temperature to one decimal place at most.

Observed Behavior

I see 42 °C 107.60000000000001 °F

This isn't always the case - e.g. on another device I see 51 °C 123.8 °F

[royreznik]

@jeremystretch I would like to provide a pr for this issue