reference the v9 short tag

Author: leafo

README.md

@@ -4,7 +4,7 @@
 
 [![Actions Status](https://github.com/leafo/gh-actions-lua/workflows/test/badge.svg)](https://github.com/leafo/gh-actions-lua/actions)
 
-**Update  Nov 18, 2020**: You must use version 8.0.0 or greater as GitHub has
+**Update  Nov 18, 2020**: You must use version 8 or greater as GitHub has
 deprecated older versions of the actions core libraries.
 
 Builds and installs Lua into the `.lua/` directory in the working directory.
@@ -22,21 +22,21 @@ Other Lua GitHub actions:
 Install Lua: (Will typically default to the latest release, 5.4.2 as of this readme)
 
 ```yaml
-- uses: leafo/gh-actions-lua@v8.0.0
+- uses: leafo/gh-actions-lua@v9
 ```
 
 Install specific version of Lua:
 
 ```yaml
-- uses: leafo/gh-actions-lua@v8.0.0
+- uses: leafo/gh-actions-lua@v9
   with:
     luaVersion: "5.1.5"
 ```
 
 Install specific version of LuaJIT:
 
 ```yaml
-- uses: leafo/gh-actions-lua@v8.0.0
+- uses: leafo/gh-actions-lua@v9
   with:
     luaVersion: "luajit-2.1.0-beta3"
 ```
@@ -107,11 +107,11 @@ jobs:
     steps:
     - uses: actions/checkout@master
 
-    - uses: leafo/gh-actions-lua@v8.0.0
+    - uses: leafo/gh-actions-lua@v9
       with:
         luaVersion: "5.1.5"
 
-    - uses: leafo/gh-actions-luarocks@v4.0.0
+    - uses: leafo/gh-actions-luarocks@v4
 
     - name: build
       run: |
@@ -144,7 +144,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@master
-    - uses: leafo/gh-actions-lua@v8.0.0
+    - uses: leafo/gh-actions-lua@v9
       with:
         luaVersion: ${{ matrix.luaVersion }}