Release Version v2.16.0

[julianbrost]

Release Workflow

• Update ICINGA2_VERSION
• Update bundled Windows dependencies
• Harden global TLS defaults (consult https://ssl-config.mozilla.org)
• Update CHANGELOG.md
• Update doc/16-upgrading-icinga-2.md if applicable
• Create and push a signed tag for the version
• Build and release DEB and RPM packages
• Build and release Windows packages
• Merge dependency updates in https://github.com/Icinga/docker-icinga2/pulls
• Create release on GitHub
• Update public docs
• Announce release

Update Bundled Windows Dependencies

Update packages.icinga.com

Add the latest Boost and OpenSSL versions to
https://packages.icinga.com/windows/dependencies/, e.g.:

• https://master.dl.sourceforge.net/project/boost/boost-binaries/1.82.0/boost_1_82_0-msvc-14.2-64.exe
• https://master.dl.sourceforge.net/project/boost/boost-binaries/1.82.0/boost_1_82_0-msvc-14.2-32.exe
• https://slproweb.com/download/Win64OpenSSL-3_0_9.exe
• https://slproweb.com/download/Win32OpenSSL-3_0_9.exe

Update Build Server, CI/CD and Documentation

• doc/win-dev.ps1 (also affects CI/CD)
• tools/win32/configure.ps1
• tools/win32/configure-dev.ps1

Re-provision Build Server

Even if there aren't any new releases of dependencies with versions
hardcoded in the repos and files listed above (Boost, OpenSSL).
There may be new build versions of other dependencies (VS, MSVC).
Our GitHub actions (tests) use the latest ones automatically,
but the GitLab runner (release packages) doesn't.

[Al2Klimov]

Re-provision Build Server

• This will fail if the GitLab runner has a new version. Consider preventing a such failure using https://git.icinga.com/infra/ansible-windows-build/-/merge_requests/55

Harden global TLS defaults

• In addition to https://ssl-config.mozilla.org, you may want to Lower leaf cert validity 397 -> 47 days #10437 (one-liner).