ci: run Forgejo Actions & Packages test w/ dynamic matrix (#1367)

Incorporates these changes:
- When `forgejo/build-from-sources` is present, Actions & Packages tests are run only against the built versions.  Otherwise, they are run against the versions defined in `$RELEASE_NUMBERS`
- Updates Packages tests which are testing Alpine publishing to use currently supported Alpine releases
- Actions & Packages tests are run in a matrix, allowing parallel execution

Only the Actions & Packages tests take a significant amount of time (>10 minutes), so changes have been limited to those test suites -- every test suite that is moved into a matrix adds additional overhead in the 1 minute `prepare-end-to-end` step.

Reviewed-on: https://code.forgejo.org/forgejo/end-to-end/pulls/1367
Co-authored-by: Mathieu Fenniak <mathieu@fenniak.net>
Co-committed-by: Mathieu Fenniak <mathieu@fenniak.net>

packages/alpine/test.sh

@@ -0,0 +1,63 @@
+#!/bin/busybox ash
+set -exuo pipefail
+
+forgejo_url=$1
+forgejo_token=$2
+
+# initialize abuild
+apk update
+apk add --no-cache alpine-sdk sudo util-linux curl
+adduser -D user -h /home/user
+addgroup user abuild
+echo "root ALL=(ALL) ALL" >/etc/sudoers
+echo "%abuild ALL=(ALL) NOPASSWD: ALL" >>/etc/sudoers
+mkdir -p /var/cache/distfiles
+chgrp abuild /var/cache/distfiles
+chmod 775 /var/cache/distfiles
+mkdir -p "/home/user/.abuild"
+echo "/home/user/.abuild/user.rsa" | abuild-keygen -i -b 4096
+echo 'PACKAGER_PRIVKEY=/home/user/.abuild/user.rsa' >/home/user/.abuild/abuild.conf
+chown -R "user:user" /home/user/
+
+# make sure we own the relevant directory
+cp -r package-source /srv/alpine
+cd /srv
+mkdir packages
+echo "REPODEST=/srv/packages" >>/home/user/.abuild/abuild.conf
+cat /home/user/.abuild/abuild.conf
+chown -R user:user alpine packages
+
+# build the package
+sudo -u user APKBUILD=alpine/forgejo-2174/APKBUILD abuild -r
+
+# build the package
+sudo -u user APKBUILD=alpine/forgejo-2173/APKBUILD abuild -r
+
+# upload new package
+cd packages/alpine/x86_64/
+for file in $(find . -name '*.apk' -type f | sed -e 's,./,,'); do
+    # remove old package
+    curl \
+        --fail \
+        -H "Authorization: token $forgejo_token" \
+        -X DELETE \
+        "$forgejo_url/api/packages/root/alpine/3.21/e2e-tests/$file" ||
+        true
+
+    # upload new package
+    curl \
+        --fail \
+        -H "Authorization: token $forgejo_token" \
+        -T "$file" \
+        "$forgejo_url/api/packages/root/alpine/3.21/e2e-tests"
+done
+
+# ensure that the install-if condition works as expected
+apk add openrc
+(cd /etc/apk/keys && curl -JO $forgejo_url/api/packages/root/alpine/key)
+echo "$forgejo_url/api/packages/root/alpine/3.21/e2e-tests" >>/etc/apk/repositories
+apk add forgejo-2174 forgejo-2173
+[ -e /usr/bin/forgejo_2174 ]    # from the installed package
+[ -e /usr/bin/forgejo_2173 ]    # from the installed package
+[ -e /etc/init.d/forgejo_2174 ] # from the -openrc package installed because of the install-if condition
+[ -e /etc/init.d/forgejo_2173 ] # from the -openrc package installed because of the install-if condition