Downgraded dependencies and updated code style

[dlundgren]

While attempting to run tests for my other PR I couldn't install any dependencies due to conflicts between this module and the 2.4.x branches of simplesamlphp itsellf.

I downgraded to the previous versions that were specified and I was able to run tests.

Other changes:

• Changed validate to verify in the composer scripts section as composer was giving A script named validate would override a Composer command and has been skipped error
• Fixed the few code styling issues that phpcs found

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.72%. Comparing base (ada397a) to head (2d75b26).
⚠️ Report is 9 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #58      +/-   ##
============================================
- Coverage     67.36%   66.72%   -0.65%     
- Complexity      342      349       +7     
============================================
  Files            26       26              
  Lines          1238     1190      -48     
============================================
- Hits            834      794      -40     
+ Misses          404      396       -8     

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