Syntax error or access violation: 1071 Specified key was too long laravel code example

Example 1: ERROR 1071 (42000) at line 76: Specified key was too long; max key length is 767 bytes laravel

'charset' => 'utf8mb4',
'collation' => 'utf8mb4_unicode_ci',

Example 2: ERROR 1071 (42000) at line 76: Specified key was too long; max key length is 767 bytes laravel

'charset' => 'utf8',
'collation' => 'utf8_unicode_ci',