issues/157: add heartbeat to BreachHandler

[komuw]

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Now,

What(What have you changed?)

• Add heartbeat to BreachHandler

Why(Why did you change it?)

• Fixes: BreachHandler should have heartbeat #157
• When using BreachHandler , it may be important to periodically make sure that your logging pipeline works even when there is nothing to log since there hasn't been a breach.
  In such a case you can enable heartbeats

References:

[codecov-io]

Codecov Report

Merging #161 into master will decrease coverage by 0.2%.
The diff coverage is 60%.

@@            Coverage Diff             @@
##           master     #161      +/-   ##
==========================================
- Coverage   86.49%   86.29%   -0.21%     
==========================================
  Files          14       14              
  Lines        1311     1321      +10     
==========================================
+ Hits         1134     1140       +6     
- Misses        177      181       +4

Impacted Files	Coverage Δ
naz/log.py	87.2% <60%> (-3.59%)	⬇️
naz/hooks.py	79.16% <0%> (ø)	⬆️
naz/client.py	80.71% <0%> (ø)	⬆️

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