release/tox.ini: no longer download packages.

My tox cannot find Python 2.7 and I don't want to help it.

release/tox.ini

@@ -3,8 +3,6 @@ envlist =
     constraints2,
     constraints38,
     constraints,
-    downloads2,
-    downloads3,
     gather,
 
 [testenv]
@@ -27,32 +25,9 @@ depends = constraints2, constraints38
 commands_pre =
 commands = python combine-constraints.py {toxinidir}
 
-[testenv:downloads2]
-# Use pip to download all pinned packages.
-basepython = python2.7
-depends = constraints
-commands_pre = pip install -U pip
-commands =
-# I tried first calling with --no-binary :all: to get source distributions
-# and then with --only-binary :all: to get binary wheels.
-# This fails at the first package that has no such distribution.
-# Uninstalling wheel did not influence this.
-    pip download -r {toxinidir}/constraints2.txt --dest {toxinidir}/dist
-# If you want to remove old dists (like a CMFPlone rc after you have done a final),
-# do 'mv dist olddist', and use the next line in both downloads2 and downloads3:
-#     pip download -r {toxinidir}/constraints.txt --dest {toxinidir}/dist --no-index --find-links {toxinidir}/olddist
-
-[testenv:downloads3]
-basepython = python3.8
-depends = constraints
-commands_pre = pip install -U pip
-commands =
-    pip download -r {toxinidir}/constraints38.txt --dest {toxinidir}/dist
-
 [testenv:gather]
 # Copy a few more files to the dist directory, for syncing with dist.plone.org.
 basepython = python3.8
-depends = downloads2, downloads3
 allowlist_externals =
     cp
     mkdir