allow uncommenting for team edition (#433)

currently, if you follow the instructions and uncomment the lines, you
will get a YAML error:

```
ERROR: yaml.parser.ParserError: while parsing a block mapping
  in "./docker-compose.yml", line 23, column 5
expected <block end>, but found '<block mapping start>'
  in "./docker-compose.yml", line 25, column 7
```

found the potential solution in mattermost/mattermost-docker#343

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

docker-compose.yml

@@ -20,9 +20,9 @@ services:
     #  - AWS_REGION=us-east-1
 
   app:
-    build: app
-      # change `build:app` to `build:` and uncomment following lines for team edition or change UID/GID
-      # context: app
+    build:
+      context: app
+      # uncomment following lines for team edition or change UID/GID
       # args:
       #   - edition=team
       #   - PUID=1000