install-openvino: make it easier to invoke on your local machine

put the default version in the shell script, not the yml.
write any files to the directory where the action lives,
and .gitignore them.

.github/actions/install-openvino/action.yml

@@ -5,7 +5,6 @@ inputs:
   version:
     description: 'The release version of OpenVINO to install'
     required: false
-    default: '2020.4.287'
 
 runs:
   using: composite