Stop publishing `heroku/buildpacks:20` and `heroku/builder-classic:22` #1044

Job	Run time
create (builder-20, amd64)	1m 14s
create (builder-22, amd64)	59s
create (salesforce-functions, amd64)	1m 3s
create (builder-24, amd64)	41s
create (builder-24, arm64)	1m 9s
test-guides (builder-20, go, amd64)	1m 7s
test-guides (builder-20, gradle, amd64)	1m 50s
test-guides (builder-20, java, amd64)	1m 4s
test-guides (builder-20, node-js, amd64)	51s
test-functions (salesforce-functions, java)	49s
test-guides (builder-20, php, amd64)	51s
test-functions (salesforce-functions, javascript)	52s
test-guides (builder-20, python, amd64)	52s
test-functions (salesforce-functions, typescript)	56s
test-guides (builder-20, ruby, amd64)	2m 14s
test-guides (builder-20, scala, amd64)	1m 38s
test-guides (builder-22, go, amd64)	53s
test-guides (builder-22, gradle, amd64)	1m 35s
test-guides (builder-22, java, amd64)	55s
test-guides (builder-22, node-js, amd64)	43s
test-guides (builder-22, php, amd64)	40s
test-guides (builder-22, python, amd64)	47s
test-guides (builder-22, ruby, amd64)	2m 9s
test-guides (builder-22, scala, amd64)	1m 26s
test-guides (builder-24, go, amd64)	51s
test-guides (builder-24, go, arm64)	1m 27s
test-guides (builder-24, python, amd64)	49s
test-guides (builder-24, python, arm64)	1m 25s
publish-images	0s
publish-indices	0s
	31m 50s

Provide feedback