github-ci: enable ubuntu-20.04 hosts for packaging

Enabling ubuntu-20.04 hosts for packaging workflows found that DEB
package Github Actions workflows do not need to install createrepo
tool. Also found that createrepo is not ready for ubuntu-20.04 as
described in (till ubuntu-21.04 where it is available as the new
version of this tool named as 'createrepo_c' as DEB package):

  3a7c2102 ('github-ci: ubuntu-20.04 misses createrepo package')

To fix it added 'createrepo_c' build and installation from sources
and changed in update_repo tool 'createrepo' tool to 'createrepo_c'.
This patch is needed to use these workflows on self-hosted runners
which run under ubuntu-20.04 by default for now.

Also checking the patch on ubuntu-20.04 hosts got the following issue:

  Regenerated DEB file: pool/xenial/main/t/tarantool/tarantool-common_2.8.0.185.g4c3e0eb-1_all.deb

  <botocore.awsrequest.AWSRequest object at 0x7f7998a4ca90>

  <botocore.awsrequest.AWSRequest object at 0x7f627d965070>
  make: *** [.gitlab.mk:131: deploy] Error 255
  Error: Process completed with exit code 2.

Found that there is already issue exists in Github Actions on it [1].
Provided solution to setup AWS region in environment helped to
workaround the issue [2].

Closes tarantool/tarantool-qa#110
Closes tarantool/tarantool-qa#111

[1]: https://github.com/aws/aws-cli/issues/5234
[2]: https://github.com/aws/aws-cli/issues/5234#issuecomment-635459464