biber: revert update to 2.18.

This reverts commit 0033d33eb9.
(#42146)

This breaks use with texlive2021.

srcpkgs/biber/patches/0001-Adapt_to_Perl_5.36.patch

@@ -0,0 +1,40 @@
+From d9e961710074d266ad6bdf395c98868d91952088 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
+Date: Wed, 25 May 2022 12:41:59 +0200
+Subject: [PATCH] Adapt to Perl 5.36
+
+A developmental release of Perl 5.36.0 fails to run tests with:
+
+    $ perl -Ilib t/basic-misc.t
+    1..72
+    Can't modify undef operator in scalar assignment at lib/Biber/Section.pm line 433, near "undef;"
+    Compilation failed in require at lib/Biber.pm line 24.
+    BEGIN failed--compilation aborted at lib/Biber.pm line 24.
+    Compilation failed in require at t/basic-misc.t line 11.
+    BEGIN failed--compilation aborted at t/basic-misc.t line 11.
+    # Looks like your test exited with 255 before it could output anything.
+
+This is because of a missing semicolon between commands in
+del_everykeys(). The new perl is more strict and raises a compile-time
+error:
+
+    $ perl -e '$a = undef $b = undef;'
+    Can't modify undef operator in scalar assignment at -e line 1, near "undef;"
+    Execution of -e aborted due to compilation errors.
+---
+ lib/Biber/Section.pm | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/Biber/Section.pm b/lib/Biber/Section.pm
+index 03ed69a51..a78942f57 100644
+--- a/lib/Biber/Section.pm
++++ b/lib/Biber/Section.pm
+@@ -429,7 +429,7 @@ sub add_everykey {
+ 
+ sub del_everykeys {
+   my $self = shift;
+-  $self->{everykey} = undef
++  $self->{everykey} = undef;
+   $self->{everykey_lc} = undef;
+   return;
+ }

srcpkgs/biber/template

@@ -1,7 +1,8 @@
 # Template file for 'biber'
 pkgname=biber
-version=2.18
-revision=1
+version=2.16
+revision=3
+reverts="2.18_1"
 build_style=perl-ModuleBuild
 hostmakedepends="perl-Module-Build"
 makedepends="perl-ExtUtils-LibBuilder"
@@ -53,4 +54,4 @@ license="Artistic-2.0"
 homepage="http://biblatex-biber.sourceforge.net"
 changelog="https://raw.githubusercontent.com/plk/biber/dev/Changes"
 distfiles="https://github.com/plk/biber/archive/v${version}.tar.gz"
-checksum=b966cf9b35a92ce9a705fec7930baab8dc2bfaf9a9f311cdb92393640222c844
+checksum=57111ebc6d0d1933e55d3fe1a92f8ef57c602388ae83598a8073c8a77fd811e2