CHANGES: Add note for 3.1.7 #357

Job	Run time
ruby-versions / Generate Ruby versions	2s
ubuntu-latest 2.7	51s
ubuntu-latest 3.0	28s
ubuntu-latest 3.1	26s
ubuntu-latest 3.2	27s
ubuntu-latest 3.3	23s
ubuntu-latest debug	39s
ubuntu-latest head	23s
macos-latest 2.7	50s
macos-latest 3.0	23s
macos-latest 3.1	38s
macos-latest 3.2	30s
macos-latest 3.3	23s
macos-latest debug	29s
macos-latest head	24s
macos-arm-oss 2.7	52s
macos-arm-oss 3.0	24s
macos-arm-oss 3.1	34s
macos-arm-oss 3.2	25s
macos-arm-oss 3.3	24s
macos-arm-oss debug	29s
macos-arm-oss head	20s
windows-latest 2.7	4m 58s
windows-latest 3.0	2m 54s
windows-latest 3.1	2m 58s
windows-latest 3.2	3m 25s
windows-latest 3.3	3m 29s
windows-latest head	2m 18s
windows-latest mingw	2m 11s
windows-latest mswin	2m 15s
	35m 12s

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