Fix Syntax Error in ice_cube gem for Ruby 3.0+ Compatibility

[codxse]

This pull request addresses a syntax error in the ice_cube gem that occurs when using Ruby 3.0 or later. The error is caused by the use of a shorthand syntax for block parameters that is not supported in earlier Ruby versions.

Current Error

SyntaxError:
       /usr/local/bundle/bundler/gems/ice_cube-db4715e37368/lib/ice_cube/schedule.rb:163: syntax error, unexpected ')', expecting local variable or method
           def each_occurrence(&)
                                ^
       /usr/local/bundle/bundler/gems/ice_cube-db4715e37368/lib/ice_cube/schedule.rb:164: syntax error, unexpected ')'
       ...rate_occurrences(start_time, &).to_a
       ...                              ^
       /usr/local/bundle/bundler/gems/ice_cube-db4715e37368/lib/ice_cube/schedule.rb:502: syntax error, unexpected `end', expecting end-of-input

This PR modifies the each_occurrence method to use the traditional block syntax, which is compatible with both older and newer Ruby versions. The changes are as follows:

# Old code
def each_occurrence(&)
  generate_occurrences(start_time, &).to_a
end

# New code
def each_occurrence(&block)
  generate_occurrences(start_time, &block).to_a
end

This change maintains the functionality while ensuring compatibility across Ruby versions.