Fixes API tests not being run using the ${BRANCH}.
make[1]: Entering directory '/home/runner/work/tackle2-hub/tackle2-hub/go-konveyor-tests'
./hub-api/run-tests.sh refs/pull/635/merge
Cloning into '/tmp/tackle2-hub-test'...
fatal: 'origin/refs/pull/635/merge' is not a commit and a branch 'api-tests-run' cannot be created from it
Fixes API tests not being run using the ${BRANCH}.
PR branch needs to be fetched.