[BUG] Issue with S2S output mode and lines over 120 char

[ghost]

Describe the bug
Exception in thread OutputThread0:
Traceback (most recent call last):
File "/usr/local/lib/python3.7/threading.py", line 926, in _bootstrap_inner
self.run()
File "/usr/local/lib/python3.7/threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/eventgen_core.py", line 318, in _worker_do_work
raise e
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/eventgen_core.py", line 304, in _worker_do_work
item.run()
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/outputplugin.py", line 39, in run
self.flush(self.events)
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/plugins/output/s2s.py", line 204, in flush
m["_time"],
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/plugins/output/s2s.py", line 173, in send_event
e = self._encode_event(index, host, source, sourcetype, _raw, _time)
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/plugins/output/s2s.py", line 124, in _encode_event
encoded_raw = self._encode_key_value("_raw", _raw)
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/plugins/output/s2s.py", line 78, in _encode_key_value
return "%s%s" % (self._encode_string(key), self._encode_string(value))
File "/usr/local/lib/python3.7/site-packages/splunk_eventgen/lib/plugins/output/s2s.py", line 69, in _encode_string
"utf-8"
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd1 in position 3: invalid continuation byte

To Reproduce
Steps to reproduce the behavior:
use outputmode=s2s

Expected behavior
no exception

Actual behavior
exception above

Do you run eventgen with SA-eventgen?
No

If you are using SA-Eventgen with Splunk (please complete the following information):
linux python 3.7
eventgen version git master

[aparajith21]

Issue can be solved by replacing utf-8 with ISO-8859-1 or charmap, both of which have a 1 to 1 mapping between bytes and characters in /splunk_eventgen/lib/plugins/output/s2s.py. Can fix please assign