Replaced dependency graph with external library.

[s3rius]

Signed-off-by: Pavel Kirilin win10@list.ru

[codecov-commenter]

Codecov Report

Merging #57 (0a7088a) into release/0.1.3 (331f282) will decrease coverage by 2.21%.
The diff coverage is 100.00%.

@@                Coverage Diff                @@
##           release/0.1.3      #57      +/-   ##
=================================================
- Coverage          66.85%   64.64%   -2.22%     
=================================================
  Files                 37       36       -1     
  Lines               1041      891     -150     
=================================================
- Hits                 696      576     -120     
+ Misses               345      315      -30     

Impacted Files	Coverage Δ
taskiq/__init__.py	100.00% <100.00%> (ø)
taskiq/abc/schedule_source.py	100.00% <100.00%> (ø)
taskiq/brokers/inmemory_broker.py	62.26% <100.00%> (ø)
taskiq/cli/worker/receiver.py	83.67% <100.00%> (ø)

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