Remove outdated comments in Dockerfile #258

Job	Run time
test (ubuntu-20.04, 3.7)	43s
test (ubuntu-20.04, 3.8)	36s
test (ubuntu-20.04, 3.9)	36s
test (ubuntu-20.04, 3.10)	45s
test (ubuntu-20.04, 3.11)	36s
test (ubuntu-20.04, 3.12)	51s
test (ubuntu-20.04, pypy3.8)	1m 27s
test (ubuntu-20.04, pypy3.9)	55s
test (ubuntu-20.04, pypy3.10)	5m 13s
test (ubuntu-22.04, 3.7)	33s
test (ubuntu-22.04, 3.8)	41s
test (ubuntu-22.04, 3.9)	33s
test (ubuntu-22.04, 3.10)	42s
test (ubuntu-22.04, 3.11)	33s
test (ubuntu-22.04, 3.12)	37s
test (ubuntu-22.04, pypy3.8)	2m 8s
test (ubuntu-22.04, pypy3.9)	58s
test (ubuntu-22.04, pypy3.10)	3m 50s
test (macos-13, 3.7)	2m 17s
test (macos-13, 3.8)	1m 40s
test (macos-13, 3.9)	1m 33s
test (macos-13, 3.10)	1m 57s
test (macos-13, 3.11)	1m 40s
test (macos-13, 3.12)	1m 46s
test (macos-13, pypy3.8)	1m 56s
test (macos-13, pypy3.9)	1m 53s
test (macos-13, pypy3.10)	8m 46s
test (windows-2022, 3.7)	2m 30s
test (windows-2022, 3.8)	2m 18s
test (windows-2022, 3.9)	2m 28s
test (windows-2022, 3.10)	1m 49s
test (windows-2022, 3.11)	1m 58s
test (windows-2022, 3.12)	2m 0s
test (windows-2022, pypy3.8)	3m 7s
test (windows-2022, pypy3.9)	2m 26s
test (windows-2022, pypy3.10)	6m 15s
builder_pypandoc	11s
builder_pypandoc_binary (macos-14)	55s
builder_pypandoc_binary (windows-2022)	1m 44s
builder_pypandoc_binary (ubuntu-22.04)	4m 40s
publisher_release	0s
publisher_latest	0s
	1h 18m 6s

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