Add Joshua Young to the list of maintainers #631

Job	Run time
Test without C extension	3m 4s
Test isolated (2.3)	3m 41s
Tests: Ruby 2.7 - ubuntu	3m 18s
Tests: Ruby 2.4 - ubuntu	3m 19s
Tests: Ruby jruby - ubuntu	6m 1s
Tests: Ruby 2.6 - ubuntu	3m 22s
Tests: Ruby 2.3 - ubuntu	3m 24s
Tests: Ruby 3.0 - ubuntu	3m 9s
Tests: Ruby 3.1 - ubuntu	3m 9s
Tests: Ruby 3.2 - ubuntu	3m 7s
Tests: Ruby 2.5 - ubuntu	3m 19s
Tests: Ruby 3.4 - ubuntu	3m 5s
Test isolated (ruby)	3m 42s
Tests: Ruby 3.3 - ubuntu	3m 15s
Tests: Ruby truffleruby - ubuntu	4m 7s
Tests: Ruby ruby - windows	4m 25s
	57m 27s

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