chore(ci): optimize end-to-end runs

* specify the version targeted by the pull request. The end-to-end
  tests previously compiled all known branches which was a waste. The
  pull request now must specify which version it is targeting so that
  only this version is recompiled and used for testing.
* when building the daily releases, use the release from the
  integration organization to ensure the tests are run against the
  latest build. Clarify in a comment why the lookup order of
  organizations is reversed in this particular case.

Refs: https://code.forgejo.org/forgejo/end-to-end/pulls/239

.forgejo/cascading-pr-end-to-end

@@ -18,6 +18,7 @@ if ! test -f forgejo/sources/$minor_version ; then
   false
 fi
 
+echo -n $minor_version >forgejo/build-from-sources
 date >last-upgrade
 
 if test -f "$forgejo_pr_or_ref"; then

.forgejo/cascading-release-end-to-end

@@ -15,8 +15,8 @@ if ! test -f $organizations ; then
   false
 fi
 #
-# do not include forgejo-experimental so that 7.0-test is found
-# in forgejo-integration where it was just built instead of
-# forgejo-experimental which was published by the previous build
+# Inverse the order of lookup because the goal in the release built
+# pipeline is to test the latest build, if available, instead of the
+# stable version by the same version.
 #
-echo forgejo forgejo-integration > $organizations
+echo forgejo-integration forgejo-experimental forgejo >$organizations