Add workflow to publish this plugin to LuaRocks

.github/workflows/release.yml

@@ -0,0 +1,18 @@
+name: "release"
+on:
+  push:
+    tags:
+      - 'v*'
+jobs:
+  luarocks-upload:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+      - name: LuaRocks Upload
+        uses: nvim-neorocks/luarocks-tag-release@v4
+        env:
+          LUAROCKS_API_KEY: ${{ secrets.LUAROCKS_API_KEY }}
+        with:
+          detailed_description: |
+            A high-performance color highlighter for Neovim which has no external dependencies!
+            Written in performant Luajit.

README.md

@@ -10,6 +10,8 @@ A high-performance color highlighter for Neovim which has **no external dependen
 
 ## Installation and Usage
 
+[![LuaRocks](https://img.shields.io/luarocks/v/norcalli/nvim-colorizer.lua?logo=lua&color=purple)](https://luarocks.org/modules/norcalli/nvim-colorizer.lua)
+
 Requires Neovim >= 0.4.0 and `set termguicolors` (I'm looking into relaxing
 these constraints). If you don't have true color for your terminal or are
 unsure, [read this excellent guide](https://github.com/termstandard/colors).