Update dependency postcss to v8.4.47 #92071

Job	Run time
Determine tests matrix	1m 16s
E2E: Build jetpack-boost	3m 7s
E2E: Build jetpack-core	3m 49s
E2E: Build jetpack-search	4m 11s
E2E: Build jetpack-social	3m 30s
E2E: Build jetpack-sync	4m 1s
E2E: Build jetpack-videopress	3m 4s
Jetpack connection e2e tests	3m 54s
Jetpack pre-connection e2e tests	2m 55s
Jetpack post-connection e2e tests	4m 50s
Jetpack sync e2e tests	4m 12s
Jetpack Boost - Base e2e tests	3m 51s
Jetpack Boost - Modules e2e tests	3m 57s
Jetpack Boost - Critical CSS e2e tests	3m 36s
Jetpack Boost - Page Cache e2e tests	3m 12s
Jetpack Boost - Concatenate JS/CSS e2e tests	3m 23s
Jetpack Boost - Image CDN e2e tests	2m 59s
Jetpack Boost - Image Guide e2e tests	3m 1s
Search e2e tests	4m 57s
VideoPress e2e tests	2m 21s
Social e2e tests	5m 37s
Test report	2s
Slack notification	1m 7s
	1h 16m 52s

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