CI: upload rockspec to LuaRocks on tag push

[luau-project]

Overview

Since https://github.com/openresty/lua-cjson has become such a core dependency to a huge amount of packages on LuaRocks, this PR adds a new job to the current CI to upload the rockspec to LuaRocks once a new tag is pushed to GitHub.

Description

• Added a upload job to CI, which uploads the rockspec to LuaRocks once a new tag is pushed to GitHub;

[!NOTE]

There is a guard to make sure that the GitHub tag matches the rockspec tag (field source.tag), failing the upload job otherwise.

• Once a new tag is pushed, this PR partially fixes https://github.com/openresty/lua-cjson/issues/96 and https://github.com/openresty/lua-cjson/issues/102 regarding the published rockspecs on LuaRocks;

• Replaced the GitHub actions leafo/gh-actions-lua@master and leafo/gh-actions-luarocks@master with luarocks/gh-actions-lua@master and luarocks/gh-actions-luarocks@master respectively, due to the former failing to install LuaJIT. See https://github.com/leafo/gh-actions-lua/issues/49 and https://github.com/leafo/gh-actions-lua/pull/50.

Requeriments

In order to upload rockspecs to LuaRocks, a few steps are required:

1. Generate an API key to upload rockspecs to LuaRocks:
   1. Visit https://luarocks.org/;
   2. Log in;
   3. Go to Settings;
   4. Generate a new API key and save it to store on a GitHub secret used by the upload job.
2. Generate a GitHub secret to hold LuaRocks API key:
   1. Visit https://github.com/openresty/lua-cjson;
   2. Log in;
   3. Go to Settings > Secrets and variables > Actions and click New repository secret button;
   4. Paste LUAROCKS_APIKEY into Name field, paste LuaRocks API key generated from LuaRocks in the Secret box, and hit Add secret button.

[!IMPORTANT]

The secret name must be LUAROCKS_APIKEY, as is defined in the upload job.

Workflow Testing

Visit my fork's workflow runs https://github.com/luau-project/lua-cjson/actions and check how it ran:

• The run https://github.com/luau-project/lua-cjson/actions/runs/11882520402 happened on a branch test-commit, which had some modifications to allow it reach the upload job (and avoiding the final upload to LuaRocks). That run was triggered by a git push;

• The run https://github.com/luau-project/lua-cjson/actions/runs/11882535036 happened on the same branch test-commit, but this time triggered by annotating a tag git tag -a "2.1.0.14" -m "Release v2.1.0.14" and pushing it to the remote repo git push origin 2.1.0.14.