[TRIVIAL] Set version to 2.4.0-b1

[ximinez]

High Level Overview of Change

This PR only changes the version number. It will be merged as
soon as Github CI actions successfully complete.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.9%. Comparing base (7506852) to head (49e0d54).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5222   +/-   ##
=======================================
  Coverage     77.9%   77.9%           
=======================================
  Files          783     783           
  Lines        66707   66707           
  Branches      8138    8140    +2     
=======================================
+ Hits         51933   51964   +31     
+ Misses       14774   14743   -31     

Files with missing lines	Coverage Δ
src/libxrpl/protocol/BuildInfo.cpp	98.2% <ø> (ø)

... and 7 files with indirect coverage changes