feat: add support for Soroban PRC's getLedgers API interface.

[overcat]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.90%. Comparing base (0fa5290) to head (fd70d50).
Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #660      +/-   ##
============================================
+ Coverage     80.88%   80.90%   +0.01%     
- Complexity     1171     1172       +1     
============================================
  Files           202      203       +1     
  Lines          4432     4436       +4     
  Branches        370      370              
============================================
+ Hits           3585     3589       +4     
  Misses          617      617              
  Partials        230      230              

Files with missing lines	Coverage Δ
src/main/java/org/stellar/sdk/SorobanServer.java	83.73% <100.00%> (+0.19%)	⬆️
...r/sdk/responses/sorobanrpc/GetLedgersResponse.java	100.00% <100.00%> (ø)