Fix Style/FormatString

Author: isuruf

.rubocop_todo.yml

@@ -35,13 +35,6 @@ Style/Documentation:
     - 'lib/symengine/iruby.rb'
     - 'lib/symengine/undef_function.rb'
 
-# Offense count: 1
-# Configuration parameters: EnforcedStyle, SupportedStyles.
-# SupportedStyles: format, sprintf, percent
-Style/FormatString:
-  Exclude:
-    - 'ext/symengine/extconf.rb'
-
 # Offense count: 1
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 # SupportedStyles: snake_case, camelCase

ext/symengine/extconf.rb

@@ -12,4 +12,4 @@
   generator = '-G "NMake Makefiles"'
 end
 
-exec 'cmake %s -DCMAKE_INSTALL_PREFIX=../../ -DRUBY_EXECUTABLE=%s %s ../../ ' % [generator, ruby_executable, ARGV.join(' ')]
+exec format('cmake %s -DCMAKE_INSTALL_PREFIX=../../ -DRUBY_EXECUTABLE=%s %s ../../ ', generator, ruby_executable, ARGV.join(' '))