fix dependency version for Ubuntu 25.04

The version of libicu on Ubuntu 25.04 is 76.
See: https://launchpad.net/ubuntu/plucky/+source/icu

Signed-off-by: Dominik Viererbe <[email protected]>

Author: dviererbe

docs/core/install/linux-ubuntu-install.md

@@ -55,7 +55,7 @@ When you install with a package manager, these libraries are installed for you.
 - ca-certificates
 - libc6
 - libgcc-s1
-- libicu74
+- libicu76
 - liblttng-ust1
 - libssl3
 - libstdc++6