ci: remove armv6 Debian images #221

Job	Run time
prepare	2m 28s
build (php-8-2-13-alpine, linux/amd64)	3m 55s
build (php-8-2-13-alpine, linux/386)	3m 14s
build (php-8-2-13-alpine, linux/arm/v6)	15m 44s
build (php-8-2-13-alpine, linux/arm/v7)	15m 14s
build (php-8-2-13-alpine, linux/arm64)	12m 47s
build (php-8-2-13-bookworm, linux/amd64)	3m 58s
build (php-8-2-13-bookworm, linux/386)	4m 33s
build (php-8-2-13-bookworm, linux/arm/v7)	15m 24s
build (php-8-2-13-bookworm, linux/arm64)	13m 8s
build (php-8-3-0-alpine, linux/amd64)	5m 0s
build (php-8-3-0-alpine, linux/386)	3m 59s
build (php-8-3-0-alpine, linux/arm/v6)	14m 43s
build (php-8-3-0-alpine, linux/arm/v7)	14m 26s
build (php-8-3-0-alpine, linux/arm64)	13m 11s
build (php-8-3-0-bookworm, linux/amd64)	4m 2s
build (php-8-3-0-bookworm, linux/386)	3m 32s
build (php-8-3-0-bookworm, linux/arm/v7)	14m 59s
build (php-8-3-0-bookworm, linux/arm64)	13m 19s
push	0s
	2h 57m 36s

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