docs: revise Docker usage instructions in README

[imbajin]

Updated Docker instructions for HugeGraph server. (Let users enable auth by default)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 40.92%. Comparing base (c0220c7) to head (ee221a7).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2882      +/-   ##
============================================
- Coverage     40.95%   40.92%   -0.04%     
  Complexity      333      333              
============================================
  Files           747      747              
  Lines         60218    60218              
  Branches       7698     7698              
============================================
- Hits          24664    24644      -20     
- Misses        32962    32980      +18     
- Partials       2592     2594       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.