convert ref branch setting anchor to script

#! /bin/bash

set -euxo pipefail

cd "${CI_PROJECT_DIR}"

# use ivas-float-update as reference for the merge source per default

FLOAT_REF_BRANCH_MERGE_SOURCE=$FLOAT_REF_BRANCH

# for porting MRs use the name-check script

if [ $CI_MERGE_REQUEST_TARGET_BRANCH_NAME = "main" -a "${CI_MERGE_REQUEST_TITLE,,}" =~ \[PORTING\] ]; then

  if [[ ! "$CI_MERGE_REQUEST_TITLE" =~ \[skip[[:space:]_-]name[[:space:]_-]check\] ]] && [[ ! "$CI_MERGE_REQUEST_TITLE" =~ \[CI\] ]]; then

    bash "${CI_PROJECT_DIR}"/ivas-codec-ci/snippets/basop/update-scripts-repo.sh

    # a bit awkward: write to file + standard out first so that the error message is visible in case of failure. Then fill the variable from the file

    ci/get_float_ref_branch_name.sh $CI_MERGE_REQUEST_SOURCE_BRANCH_NAME | tee tmp_ref_branch.txt

    FLOAT_REF_BRANCH_MERGE_SOURCE=$(cat tmp_ref_branch.txt)

  fi

fi

# TODO: remove after merge to main

FLOAT_REF_BRANCH_MERGE_SOURCE=float-pc