How to set env variable from gitlab ci cd dynamically - docker

Question

I would like to edit the gitlab cicd variables thru my pipeline script.
Flow:
Submit merge request
CI pipeline retrieve the version number (variable stored in the CICD project setting (refer to pic although the variable version is not included)
version+1 and set back into the CICD project setting
git tag the file based on version number
the file i want to git tag is a bash script file and I am using Linuxx docker image. please advise
current script
variables:
PROFILE_NAME: default
default:
image: docker-image
stages:
- tagging
Tag:
stage: tag
script:
- yum install git -y
- git --version
- git remote set-url --push origin ${CI_SERVER_PROTOCOL}://${GITLAB_PERSONAL_ACCESS_TOKEN_NAME}:${GITLAB_PERSONAL_ACCESS_TOKEN}#${CI_SERVER_HOST}/${CI_PROJECT_PATH}.git
- export "VERSION=$(($VERSION +1 ))" > $INC_VERSION
- echo 'after version:' $VERSION
- echo 'after increment version:' $INC_VERSION
- git push origin --tags
only:
refs:
- merge_requests
variables:
- ($CI_MERGE_REQUEST_TARGET_BRANCH_NAME =~ /^dev/ || $CI_COMMIT_BRANCH =~ /^dev/ || $CI_MERGE_REQUEST_TARGET_BRANCH_NAME =~ /^release-/ || $CI_COMMIT_BRANCH =~ /^release-/)
except:
variables:
- ($CI_COMMIT_BEFORE_SHA == '0000000000000000000000000000000000000000' && $CI_MERGE_REQUEST_TARGET_BRANCH_NAME !~ /^./)