[release auto] use python3 for interpreter (#46800)

python is not installed by default in the forge.

Signed-off-by: Lonnie Liu <[email protected]>

.buildkite/release-automation/set-ray-version.sh

@@ -3,7 +3,7 @@
 set -euo pipefail
 
 if [[ -z "${RAY_VERSION:-}" ]]; then
-    RAY_VERSION="$(python python/ray/_version.py | cut -d' ' -f1)"
+    RAY_VERSION="$(python3 python/ray/_version.py | cut -d' ' -f1)"
     if [[ "${RAY_VERSION}" =~ dev0 ]]; then
         echo "RAY_VERSION is not set, value is ${RAY_VERSION}" >/dev/stderr
         exit 1