Changes

chore(jenkins/pipelines/devbuild): update gethash image tag in dev-build (#3534)

This commit changes the image tag for the gethash container in the
dev-build.groovy file from 'latest' to 'v20250526', ensuring the use of
a specific version for improved stability and predictability in the
build process.

* gethash.py from
https://github.com/PingCAP-QE/ci/blob/main/scripts/artifacts/gethash.py
* support gitRef like commit/xxx in gethash.py
 (commit: 7da50a8)