readme: fix typo

README.md

@@ -383,7 +383,7 @@ Connection Instance Methods
     * **tlsOptions** - < _object_ > - Options object to pass to tls.connect() **Default:** (none)
     * **autotls** - < _string_ > - Set to 'always' to always attempt connection upgrades via STARTTLS, 'required' only if upgrading is required, or 'never' to never attempt upgrading. **Default:** 'never'
     * **connTimeout** - < _integer_ > - Number of milliseconds to wait for a connection to be established. **Default:** 10000
-    * **keepalive** - < _boolean_ > - Enable the keepalive mechnanism. **Default:** true
+    * **keepalive** - < _boolean_ > - Enable the keepalive mechanism. **Default:** true
     * **debug** - < _function_ > - If set, the function will be called with one argument, a string containing some debug info **Default:** <no debug output>
 
 * **connect**() - _(void)_ - Attempts to connect and authenticate with the IMAP server.