Improve self-hosted detection

Author: shivammathur

src/scripts/unix.sh

@@ -53,7 +53,9 @@ read_env() {
   [ "${debug:-${DEBUG:-false}}" = "true" ] && debug=debug && update=true || debug=release
   [[ "${phpts:-${PHPTS:-nts}}" = "ts" || "${phpts:-${PHPTS:-nts}}" = "zts" ]] && ts=zts && update=true || ts=nts
   fail_fast="${fail_fast:-${FAIL_FAST:-false}}"
-  [[ -z "${ImageOS}" && -z "${ImageVersion}" || -n ${ACT} ]] && _runner=self-hosted || _runner=github
+  [[ ( -z "$ImageOS" && -z "$ImageVersion" ) ||
+     ( -n "$RUNNER_ENVIRONMENT" && "$RUNNER_ENVIRONMENT" = "self-hosted" ) ||
+     -n "$ACT" || -n "$CONTAINER" ]] && _runner=self-hosted || _runner=github
   runner="${runner:-${RUNNER:-$_runner}}"
   tool_path_dir="${setup_php_tools_dir:-${SETUP_PHP_TOOLS_DIR:-/usr/local/bin}}"