test lower caser... smh

It's hot. Am not very smart.

```
➜  elixir-common git:(main) MIX_ENV=TEST mix docs
Generated together app
** (Mix) The task "docs" could not be found. Did you mean "do"?
➜  elixir-common git:(main) MIX_ENV=test mix docs
Generating docs...
View "html" docs at "doc/index.html"
```

Author: PragTob

.github/workflows/main.yml

@@ -40,7 +40,7 @@ jobs:
           mix local.hex --force
           mix local.rebar --force
           mix deps.get
-          MIX_ENV=TEST mix docs
+          MIX_ENV=test mix docs
 
       - name: Upload Docs
         id: docs