[backend] compat with OBS 2.11 patchinfo format

Add "Update of the Base Distributions" section to the release notes

... the release notes

Switch to test 15.5 build

Remove rebuild workflow

We set the version inside our service to the last tag manually

https://github.com/openSUSE/open-build-service/wiki/OBS-Minor-Release-HOWTO#update-obs-server-package-in-staging

No need to rebuild this on every merge to 2.10

Switch to branch_package and test 15.4 build

[dist] update Gemfile.lock for rspec testsuite

link_package can't run source services anymore...

Fixes conflicts between nokogiri (1.10.9) and glibc

SEE
https://github.com/sparklemotion/nokogiri/pull/2106
for more information.

[dist] obsapisetup: create openssl key with 4096

This is required since opensuse 15.4. Otherwise apache will fail with a config error

[ci] updated test fixtures to newer distros

Add release notes for 2.10.21

Update bundled gem rack version

We need to point obs-server to the updated rack version

🚨 [security] [src/api - 2.10] Update rack: 2.2.6.2 → 2.2.6.4 (patch)

Add release notes for 2.10.20

🚨 [security] [src/api - 2.10] Update globalid: 1.0.0 → 1.0.1 (patch)

🚨 [security] [src/api - 2.10] Update rack: 2.2.4 → 2.2.6.2 (minor)

Nowadays ^ is allowed to be in versions, i.e. also in filenames.

[dist] Add release notes for 2.10.19

🚨 [security] [src/api - 2.10] Update rails-html-sanitizer: 1.3.0 → 1.4.4 (minor)

fix emulated build with OBS_VM_TYPE=qemu:$arch in 2.10 branch

backport commit 4defddcf did miss some conditionals and thus
broke emulated builds on 2.10 releases

Otherwise we lose the proxy information and the fetch of the
project config will fail.