Rework the build and CI: swap to SourceMod's safetyhook-based CDetour and
drop the vendored CDetour/asm sources, the old Makefile, Travis config, and
buildbot perl scripts. Add GitHub Actions building and releasing x86 and
x86_64 against SM 1.12 and 1.13, plus dependabot. Split the Windows and Linux
packages and tidy naming.
Gate IPluginManager::FindPluginByContext on the extension API version so the
extension builds against both SM 1.12 (API 8) and 1.13 (API 9), and shim
DETOUR_CREATE_STATIC_FIXED over the address overload safetyhook exposes.
Deprecate SteamWorks_ForceHeartbeat: newer Steamworks SDKs removed
ISteamGameServer::ForceHeartbeat, so make the native a no-op and mark it
deprecated in the include.
Nicholas Hastings
Ryan Stecker