autopkgtest failures with ruby-defaults 1:3.3~ubuntu3

[Pushkar Kulkarni]

 The bsfilter autopkgtests fail [1] with Ruby 3.3.

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 80s /usr/bin/bsfilter:90:in `initialize': wrong number of arguments (given 3, expected 1..2) (ArgumentError)
 80s
 80s RE_UTF8 = Regexp.new(PATTERN_UTF8, nil, 'n')
 80s ^^^^^^^^^^^^^^^^^^^^^^
 80s from /usr/bin/bsfilter:90:in `new'
 80s from /usr/bin/bsfilter:90:in `<class:Bsfilter>'
 80s from /usr/bin/bsfilter:22:in `<top (required)>'
 80s from test.rb:4:in `load'
 80s from test.rb:4:in `<main>'

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This error arises because Regexp in Ruby 3.3 no longer takes 3 arguments. See the release notes here [2] and the related bug here [3].
[1] https://autopkgtest.ubuntu.com/results/autopkgtest-oracular/oracular/amd64/b/bsfilter/20240820_073330_e88ad@/log.gz
[2] https://www.ruby-lang.org/en/news/2023/12/25/ruby-3-3-0-released/
[3] https://bugs.ruby-lang.org/issues/18797

[Pushkar Kulkarni (pushkarnk)]

Regexp::compile is an alias for Regexp::new. The fix needs to be extended to ::compile too.