refactor!: Rename versionKey to variationKey #374

Job	Run time
go-versions / go-versions	3s
go-versions / go-versions	3s
Windows, Go 1.23	2m 9s
Windows, Go 1.23	2m 35s
Windows, Go 1.22	2m 29s
Windows, Go 1.22	2m 29s
Windows, Go 1.18	1m 4s
Windows, Go 1.18	1m 4s
Linux, Go 1.18 / Benchmarks	4m 48s
Linux, Go 1.18 / Benchmarks	4m 48s
Linux, Go 1.18 / Contract Tests	1m 25s
Linux, Go 1.18 / Contract Tests	1m 25s
Linux, Go 1.18 / Unit Tests and Coverage	1m 5s
Linux, Go 1.18 / Unit Tests and Coverage	1m 5s
Linux, Go 1.22 / Benchmarks	4m 39s
Linux, Go 1.22 / Benchmarks	4m 39s
Linux, Go 1.22 / Contract Tests	1m 14s
Linux, Go 1.22 / Contract Tests	1m 14s
Linux, Go 1.22 / Unit Tests and Coverage	1m 5s
Linux, Go 1.22 / Unit Tests and Coverage	1m 5s
Linux, Go 1.23 / Benchmarks	4m 32s
Linux, Go 1.23 / Benchmarks	4m 32s
Linux, Go 1.23 / Contract Tests	1m 18s
Linux, Go 1.23 / Contract Tests	1m 18s
Linux, Go 1.23 / Unit Tests and Coverage	1m 2s
Linux, Go 1.23 / Unit Tests and Coverage	1m 2s
	54m 12s

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