location of bibcop.pl is broken

See #20, release log:

• e9346ab by @yegor256: #20 year up to 2023
• 1aef385 by @yegor256: #20 extra test
• d9aacd7 by @yegor256: #20 doc
• e9e8854 by @yegor256: #20 error in error reporting f...
• 757cc45 by @yegor256: #20 script option
• d6f65ca by @yegor256: typo
• 373ce6b by @yegor256: typo
• 6931ba0 by @yegor256: notice

Released by Rultor 2.0-SNAPSHOT, see build log