Bump version to 0.26.2; update CHANGELOG #244

Job	Run time
Test against Ruby 3.0 / ActiveModel 6.1	21s
Test against Ruby 3.0 / ActiveModel 7.0	20s
Test against Ruby 3.0 / ActiveModel 7.1	1m 23s
Test against Ruby 3.1 / ActiveModel 6.1	21s
Test against Ruby 3.1 / ActiveModel 7.0	19s
Test against Ruby 3.1 / ActiveModel 7.1	20s
Test against Ruby 3.1 / ActiveModel 7.2	19s
Test against Ruby 3.2 / ActiveModel 6.1	22s
Test against Ruby 3.2 / ActiveModel 7.0	20s
Test against Ruby 3.2 / ActiveModel 7.1	21s
Test against Ruby 3.2 / ActiveModel 7.2	21s
Test against Ruby 3.2 / ActiveModel 8.0	20s
Test against Ruby 3.3 / ActiveModel 6.1	22s
Test against Ruby 3.3 / ActiveModel 7.0	19s
Test against Ruby 3.3 / ActiveModel 7.1	18s
Test against Ruby 3.3 / ActiveModel 7.2	20s
Test against Ruby 3.3 / ActiveModel 8.0	20s
Test against Ruby 3.4.0-preview2 / ActiveModel 7.1	1m 34s
Test against Ruby 3.4.0-preview2 / ActiveModel 7.2	1m 21s
Test against Ruby 3.4.0-preview2 / ActiveModel 8.0	1m 30s
	11m 11s

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