Update mdlayher/apcupsd dependency

[rlenferink]

This updates the mdlayher/apcupsd dependency to the latest commit. This contains a fix for the apcupsd input plugin. The problem that otherwise occurred is (in Telegraf v1.16.2):

2020-11-20T14:06:51Z E! [inputs.apcupsd] Error in plugin: can't parse time: "02/19/2020"

Updating the dependency results in a working input plugin again:

[root@monitoring-vm1 ~]# ./telegraf -config telegraf-test.conf -test
2020-11-20T15:54:13Z I! Starting Telegraf
> apcupsd,host=monitoring-vm1.loc,model=Smart-UPS\ 3000,serial=AS2008161454,status=ONLINE,ups_name=APCUPS battery_charge_percent=100,battery_date="02/19/2020",battery_voltage=54,firmware="UPS 09.3 (ID18)",input_frequency=50,input_voltage=226,internal_temp=18,load_percent=10,nominal_battery_voltage=0,nominal_input_voltage=0,nominal_power=0i,output_voltage=228,status_flags=83886088i,time_left_ns=6480000000000i,time_on_battery_ns=0i 1605887653000000000

Fixes #6675

Pinging @danielnelson for review and merge.

My output when executing apcaccess:

[root@monitoring-vm1 ~]# apcaccess
APC      : 001,042,1001
DATE     : 2020-11-20 16:52:41 +0100
HOSTNAME : monitoring-vm1.loc
VERSION  : 3.14.14 (31 May 2016) redhat
UPSNAME  : APCUPS
CABLE    : Ethernet Link
DRIVER   : SNMP UPS Driver
UPSMODE  : Stand Alone
STARTTIME: 2020-11-20 14:36:21 +0100
MODEL    : Smart-UPS 3000
STATUS   : ONLINE
LINEV    : 226.0 Volts
LOADPCT  : 9.0 Percent
BCHARGE  : 100.0 Percent
TIMELEFT : 103.0 Minutes
MBATTCHG : 30 Percent
MINTIMEL : 30 Minutes
MAXTIME  : 0 Seconds
MAXLINEV : 227.0 Volts
MINLINEV : 226.0 Volts
OUTPUTV  : 228.0 Volts
SENSE    : High
DLOWBATT : 15 Minutes
LOTRANS  : 207.0 Volts
HITRANS  : 253.0 Volts
ITEMP    : 18.0 C
ALARMDEL : 30 Seconds
BATTV    : 55.0 Volts
LINEFREQ : 50.0 Hz
LASTXFER : Automatic or explicit self test
NUMXFERS : 0
TONBATT  : 0 Seconds
CUMONBATT: 0 Seconds
XOFFBATT : N/A
SELFTEST : OK
STESTI   : OFF
STATFLAG : 0x05000008
MANDATE  : 02/19/2020
SERIALNO : AS2008161454
BATTDATE : 02/19/2020
NOMOUTV  : 230 Volts
FIRMWARE : UPS 09.3 (ID18)
END APC  : 2020-11-20 16:53:06 +0100

Required for all PRs:

• Signed CLA.
• Associated README.md updated.
• Has appropriate unit tests.

[srebhan]

This probably requires a go mod tidy as revealed by make check. Could you please fix the CI problems and update this PR!?

[rlenferink]

Thanks for the suggestion @srebhan ! I think I just beat you to it with the force push I did ;)

[rlenferink]

The unit tests for the plugin were failing (forgot to update). I just updated the unit test to match with the behavior of the used library. Instead of parsing it as a time.Time object it is now returned as a string where input == output. See the following commit for further insights: mdlayher/apcupsd@149abe0