lua-rocks: update to 3.7.0

## What's new in LuaRocks 3.7.0

* Improved connectivity resiliency
  * LuaRocks can now use mirrors for downloading rocks even if downloading
    the manifest from the main server succeeds.
    In previous versions, LuaRocks would check whether to use a mirror in the first
    download operation, when it fetches the manifest. Once the server
    (luarocks.org or one of its default mirrors) was chosen, it would stick with
    it for the rest of the command.
    The resulting behavior was that if the manifest fails to load, it switches to
    a mirror and continues from there. But if the manifest fetches ok and the then
    actual rock download fails, it would give up, instead of trying that in a
    mirror as well.
    Now, it retries every download on a mirror whenever the base URL matches one
    configured in cfg.rocks_servers. The original behavior was satisfactory if
    there was complete downtime in the main server, but this new behavior should
    make the CLI much more resilient with regard to any intermittent failures
    happening on the main server.
* On Unix, it now respects environment variables $XDG_CACHE_HOME and $XDG_CONFIG_HOME
  * This means the user's configuration typically resides in ~/.config/luarocks/
    as per the XDG standard
  * The legacy path ~/.luarocks/ continues to be tested first, for backwards
    compatibility
* Fixes check for the default Lua version set in the user's home configuration
* Fixes an issue on Windows where it would incorrectly revoke permissions
  from the current user when installing

## What's new in LuaRocks 3.6.0

* Adds a double-check step to verify that all files from a rock are installed
* Improve resilience of the manifest reader to deal with manifests
  written with older versions of LuaRocks lower than 3.0
* `luarocks pack` now checks that the directory inside the archive being packed
  as a `.src.rock` actually exists, refusing to pack an invalid rock from
  a badly configured rockspec.
* Fixes behavior of `luarocks pack` when the `url` entry of a rockspec
  points to a bare file.
* Remove an entry from the manifest if the rock itself is already missing
* The `configure` script now checks that the version of `lua.h`
  found matches that of the Lua interpreter detected or configured
* Fixes the renaming of scripts when multiple versions are installed
* Fixes availability check for `svn` for rockspecs using Subversion
* Fixes for running with an empty PATH environment variable
* Portability improvements:
  * Windows: vcvarsall.bat output is now properly redirected to NUL
    meaning that the output of `luarocks path` can be used in scripts
  * Fixes autodetection for Cygwin
  * Handles macOS versions greater than 10.10
  * Adds platform specific configurations for NetBSD
  * Respects CC/CFLAGS/LDFLAGS on FreeBSD
* Luacheck now runs on the LuaRocks CI
* Distributed binaries are built using Lua 5.3


(nia)