chore(deps): update gentoo/stage3:latest docker digest to 81c5780

Author: renovate-bot

docker/Dockerfile_gentoo

@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 # Gentoo is known for its customization, optimization at the expense of image build time.asdf
 # This Dockerfile offers a stable base image but takes extra time to compile all dependencies.
-FROM gentoo/stage3:latest@sha256:4e9f9abb123542925353417fb7116ec981989cdfc5b9871f5a40969482e05ec3
+FROM gentoo/stage3:latest@sha256:81c5780ca5e592b1ed04f18109e0d47510f1291c077a1a95ba9441dded204187
 
 # Set the terminal type to Xterm.
 ENV TERM=xterm