[infra] Make kubectl executable in asset

Change-Id: I23937444600c0da2c6a9b4813c04ae335e7e3aff
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/607008
Auto-Submit: Eric Boren <borenet@google.com>
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
2 files changed