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add validation in kubectl create if no file in directory
**What this PR does / why we need it**:
if no yaml or json file in a directory
```
# ./cluster/kubectl.sh create -f ../0/1 --dry-run
pod "nginx" created (dry run)
# ./cluster/kubectl.sh create -f ../0
error: You must provide one or more resources by argument or filename.
Example resource specifications include:
'-f rsrc.yaml'
'--filename=rsrc.json'
'<resource> <name>'
'<resource>'
```
expected:
```
# ./cluster/kubectl.sh create -f ../0
error: error reading [../0]: please make sure the file extension is [.json .yaml .yml]
```
**Which issue this PR fixes**: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
c36e66dd66