Fix composer package name should be all lowercase

Deprecation warning: require.phpFastCache/phpfastcache is invalid,
it should not contain uppercase characters. Please use
phpfastcache/phpfastcache instead. Make sure you fix this
as Composer 2.0 will error.

Signed-off-by: Jack Cherng <[email protected]>

Author: jfcherng

README.md

@@ -234,7 +234,7 @@ As Fast To Implement As Opening a Beer
 
 
 ```bash
-composer require phpFastCache/phpFastCache
+composer require phpfastcache/phpfastcache
 ```
 
 #### :construction: Step 2: Setup your website code to implement the phpFastCache calls (with Composer)