[hotfix] Ignore the local directories check-license.sh creates

[weiqingy]

Purpose of change

tools/check-license.sh creates two directories in the repository root before it runs:

• mkdir -p "$FWDIR"/lib (line 65) for the Apache RAT jar it downloads
• mkdir -p build (line 72) for the rat-results.txt it writes

Neither was in .gitignore, so anyone who runs the repository's own license check ends up with ?? build/ and ?? lib/ sitting in git status from then on.

Both patterns are anchored to the root (/build/, /lib/) so that nested directories of the same name keep matching their own existing rules. In particular python/flink_agents/lib/ still matches its own entry rather than the new one, and no tracked file is affected: git ls-files build lib is empty.

Tests

Not applicable, this only changes .gitignore. Verified with git check-ignore -v:

build                      .gitignore:16:/build/    build
lib                        .gitignore:17:/lib/      lib
python/flink_agents/lib    .gitignore:25:python/flink_agents/lib/    python/flink_agents/lib

After the change, tools/check-license.sh leaves a clean git status.

API

No.

Documentation

• doc-needed
• doc-not-needed
• doc-included

[weiqingy]

The one failing check is unrelated to this PR.

• cross-language [ubuntu-latest] [python-3.12] [java-21]: the Start Milvus step failed pulling images from Docker Hub with milvus-standalone Error Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers). The Run e2e tests step was then skipped, so no test actually ran. Evidence: failing job.

This PR only adds two lines to .gitignore, and touches no code, workflow, or compose file. The same cross-language job passed on a run that started about a minute later, so the pull timeout looks transient. Evidence: passing job.