Add edges to existing graph.

[siyuan0322]

Add edges to existing graph.

Must merge v6d-io/v6d#222 first and make a image.

[codecov-io]

Codecov Report

Merging #179 (7b26e8a) into main (d709119) will decrease coverage by 19.42%.
The diff coverage is 84.61%.

@@             Coverage Diff             @@
##             main     #179       +/-   ##
===========================================
- Coverage   78.86%   59.43%   -19.43%     
===========================================
  Files          51       52        +1     
  Lines        4669     4738       +69     
===========================================
- Hits         3682     2816      -866     
- Misses        987     1922      +935     

Impacted Files	Coverage Δ
python/graphscope/framework/graph.py	75.32% <71.42%> (-14.49%)	⬇️
python/graphscope/framework/graph_builder.py	78.57% <78.57%> (ø)
python/graphscope/framework/graph_utils.py	81.15% <80.00%> (-8.25%)	⬇️
python/graphscope/framework/dag_utils.py	45.31% <90.90%> (-18.22%)	⬇️
python/graphscope/__init__.py	100.00% <100.00%> (ø)
python/graphscope/deploy/tests/test_demo_script.py	99.24% <100.00%> (+0.08%)	⬆️
python/graphscope/analytical/udf/patch.py	3.47% <0.00%> (-96.53%)	⬇️
python/graphscope/analytical/udf/wrapper.py	25.80% <0.00%> (-74.20%)	⬇️
python/graphscope/analytical/udf/decorators.py	21.25% <0.00%> (-73.75%)	⬇️
python/graphscope/analytical/udf/compile.py	25.41% <0.00%> (-65.09%)	⬇️
... and 21 more

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[sighingnow]

Update the requirements.txt as well.