Bump postcss from 8.4.37 to 8.4.38 #2489

Job	Run time
test-ruby-matrix (4, 0)	2m 45s
test-ruby-matrix (4, 1)	2m 17s
test-ruby-matrix (4, 2)	2m 23s
test-ruby-matrix (4, 3)	2m 59s
CodeQL SAST scan / Analyze	1m 27s
Dependency Review scan / dependency-review-pr	5s
Dependency Review scan / dependency-review-push	0s
SNYK security analysis / sast	11s
SNYK security analysis / sca	12s
Lint JavaScript / Run Standardx	16s
Lint Ruby / Run RuboCop	13s
Lint SCSS / Run Stylelint	17s
Security Analysis / Run Brakeman	10s
Test JavaScript / Run Jasmine	46s
Test Ruby	1s
	14m 2s

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