add lib changelog for v1.50.13 (#1253)

Author: Tofel

lib/.changeset/v1.50.13.md

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+- Updates a lot of Go dependencies for the lib and tools
+- Updates all GHA actions to latest versions
+- Updates default Docker image versions for all Eth2 clients to latest
+- Fixes "chain ready" condition for Reth v1.1.0
+- Fixes regex used for selecting Docker image tags that need to be mirrored to be less greedy
+- Fixes how we extract version and package name from tag for tags with subpackages