Bump govuk_publishing_components from 35.19.0 to 35.20.0 #1018

Job	Run time
Lint JavaScript / Run Standardx	15s
Lint Ruby / Run RuboCop	30s
Lint SCSS / Run Stylelint	17s
Security Analysis / Run Brakeman	21s
Test JavaScript / Run Jasmine	51s
Test Ruby / Run Minitest	5m 41s
	7m 55s

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