Revert "fix typo in README (#1247)"

This reverts commit 5715200.

Erroneously applied this PR, this is not a typo. You can provide a
"-FLAGNAME" to negate a flag.

Author: sodabrew

README.md

@@ -316,7 +316,7 @@ development:
   host: 127.0.0.1
   port: 3306
   flags:
-    - COMPRESS
+    - -COMPRESS
     - FOUND_ROWS
     - MULTI_STATEMENTS
   secure_auth: false