Update xeus-cpp-lite build instruction in README

[anutosh491]

Description

Minor change, getting rid of redundant flag

Type of change

Please tick all options which are relevant.

• Bug fix
• New feature
• Added/removed dependencies
• Required documentation updates

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.80%. Comparing base (d8b8a93) to head (52d04c6).
⚠️ Report is 155 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #192   +/-   ##
=======================================
  Coverage   80.80%   80.80%           
=======================================
  Files          19       19           
  Lines         974      974           
  Branches       93       93           
=======================================
  Hits          787      787           
  Misses        187      187           

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[anutosh491]

Minor change. Nothing much to review. Heavy lifting for introducing this change in the CI was done in #190