* PE-36459 .sync.yml and pdk updated

* PE-36461 Pull request template added

* PE-36461 Spec and acceptance tests added to checklist

Co-authored-by: Ioannis Karasavvaidis <32846251+CoMfUcIoS@users.noreply.github.com>

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Co-authored-by: Ioannis Karasavvaidis <32846251+CoMfUcIoS@users.noreply.github.com>

Starting with PE 2023.3, updates to r10k libraries from PE-35980 changes
in libgit2 now verify host keys. Because of this code manager now needs
to be configured with known hosts public key information for the r10k
remote host. Without this, PE will install but code manager will fail to
deploy.

This patch will fail the plan early if installing PE 2023.3+, with
r10k_private_key (so using ssh protocol) and no r10k_known_hosts array.

Updated Rubocop config.
Generated TODO and fixed minor issue.

Since we aren't testing whether r10k_remote using git@ or ssh:// also
has r10k_private_key set, testing for r10k_known_hosts seems like
overkill. Removing that plan_fail, and setting r10k_known_hosts directly
in the generate_pe_conf call alongside the other r10k parameters.

It's true that this parameter only exists in 2023.3+, but
peadm::generate_pe_conf() will drop parameters with undef values, and if
r10k_known_hosts is explicitly set by mistake by a user on an earlier
version than 2023.3, an unmatched parameter in pe.conf hiera is not
fatal.

Adding optional parameter for r10k known hosts
Alerting user to set known hosts if they are upgrading to or past 2023.3

8016fbe
introduced a few functions calls that are only available in stdlib 9 and
newer.

security teams frequently overlook allowing the standard pgpkeyserver port
fortunately the ubuntu keyserver also responds on port 80

…o PE-36789

(PE-36580) Add r10k_known_hosts to install plan

Noticed that the get_pe_conf/update_pe_conf functions were expecting a
target but $primary_target is actually an array. So I went ahead added
specs covering the basic cases for upgrade and r10k_known_hosts. They
aren't the best specs due to difficulties testing write_file,
upload_file and out_message, but they at least validate that the plan
completes with r10k_known_hosts set.

(PE-36789) R10k Known hosts upgrade path

Also changed test matrix to use latest verion

Co-authored-by: GitHub Actions <puppetlabs@users.noreply.github.com>

This reverts commit fa17f31.

Co-authored-by: GitHub Actions <puppetlabs@users.noreply.github.com>