Add optional s6-overlay symlink packages

These packages create symlinks to various s6-overlay
tools in /usr/bin for convenience.

See: https://github.com/just-containers/s6-overlay?tab=readme-ov-file#releases

Change-type: minor
Signed-off-by: Kyle Harding <kyle@balena.io>

.github/actions/test/action.yml

@@ -112,6 +112,7 @@ runs:
         python3 --version
         pwsh -Version
         runc --version
+        s6-rc help
         socat -V
         yq --version
         zstd --version

runner/Dockerfile

@@ -119,11 +119,24 @@ RUN eget just-containers/s6-overlay \
     --all --file "*" --to "./" \
     --tag "${S6_OVERLAY_VERSION}"
 
+# hadolint ignore=DL3059
 RUN eget just-containers/s6-overlay \
     --asset "s6-overlay-noarch.tar.xz" \
     --all --file "*" --to "./" \
     --tag "${S6_OVERLAY_VERSION}"
 
+# hadolint ignore=DL3059
+RUN eget just-containers/s6-overlay \
+    --asset "s6-overlay-symlinks-noarch.tar.xz" \
+    --all --file "*" --to "./" \
+    --tag "${S6_OVERLAY_VERSION}"
+
+# hadolint ignore=DL3059
+RUN eget just-containers/s6-overlay \
+    --asset "s6-overlay-symlinks-arch.tar.xz" \
+    --all --file "*" --to "./" \
+    --tag "${S6_OVERLAY_VERSION}"
+
 ####################################################################################################
 
 FROM eget-build AS go-github-apps
@@ -365,6 +378,7 @@ RUN aws --version && \
     pwsh -Version && \
     python3 --version && \
     runc --version && \
+    s6-rc help && \
     socat -V && \
     yq --version && \
     zstd --version