Fix: jpeg invalid byte sequence when checking unused

[keymastervn]

I got this error backtrace when i18n-tasks unused -l en

/Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/pattern_scanner.rb:42:in `scan': invalid byte sequence in UTF-8 (ArgumentError)
  7: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/scanner_multiplexer.rb:34:in `block (3 levels) in collect_results'
  6: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/file_scanner.rb:26:in `keys'
  5: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/file_scanner.rb:57:in `traverse_files'
  4: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/files/file_finder.rb:30:in `traverse_files'
  3: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/files/file_finder.rb:30:in `map'
  2: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/file_scanner.rb:27:in `block in keys'
  1: from /Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/pattern_scanner.rb:42:in `scan_file'
/Users/dat/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/i18n-tasks-0.9.34/lib/i18n/tasks/scanners/pattern_scanner.rb:42:in `scan': Error scanning app/assets/images/intrust_super_logo.jpeg: invalid byte sequence in UTF-8 (I18n::Tasks::CommandError)
i18n-tasks: Error scanning app/assets/images/intrust_super_logo.jpeg: invalid byte sequence in UTF-8

Added *.jpeg to ALWAYS_EXCLUDE