Bump the version to 0.99 and require collocatordb 1.8.0

The explanations added for LD, LDaf and the effective window size only
hold with collocatordb 1.8.0, where Log-Dice follows Rychly's
definition. Built against an older one, the interface would show the
previous LD values under the new text, without anything indicating the
mismatch, so the minimum version is raised from 1.5.0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Change-Id: Ib8d7ca9e69bbc065d04684da3aa1d662b253d46d
diff --git a/script/derekovecs-server b/script/derekovecs-server
index 184bed0..c69ef28 100755
--- a/script/derekovecs-server
+++ b/script/derekovecs-server
@@ -1,6 +1,6 @@
 #!/usr/bin/env perl
 
-our $VERSION = '0.98';
+our $VERSION = '0.99';
 
 use IDS::DeReKoVecs::Read;
 use Mojolicious::Lite;