Add repository path to Git safe.directory

Required because the owner inside containers is different, likely root,
and git doesn't allow that by default.

ci/github/install.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# Copyright 2021 Alexander Grund
+# Copyright 2021-2025 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 #      http://www.boost.org/LICENSE_1_0.txt)
@@ -13,6 +13,10 @@
 
 set -ex
 
+# Required because inside a container the owner is root so git commands would fail.
+# Note that $GITHUB_WORKSPACE != ${{github.workspace}} (in the CI yml) inside containers.
+git config --global --add safe.directory "$GITHUB_WORKSPACE" || echo "Failed to set Git safe.directory" # Don't fail, just warn
+
 BOOST_CI_TARGET_BRANCH="${GITHUB_BASE_REF:-$GITHUB_REF}"
 export BOOST_CI_TARGET_BRANCH="${BOOST_CI_TARGET_BRANCH##*/}" # Extract branch name
 export BOOST_CI_SRC_FOLDER="${GITHUB_WORKSPACE//\\//}"
@@ -64,4 +68,4 @@ fi
   [ -z "$B2_TARGETS" ] || echo "B2_TARGETS=$B2_TARGETS"
  # Filter out (only) the conditions from set -x
  # Write the stdout to the GitHub env file
-} 2> >(grep -vF ' -z ' >&2) >> "$GITHUB_ENV"
+} 2> >(grep -vF ' -z ' >&2) >> "$GITHUB_ENV"