Spinner - warn isSVG prop default value now true

[evwilkin]

Follow up to breaking change PR patternfly/patternfly-react#8183

We changed the default value of the isSVG prop from false to true, and should look to potentially send a warning to users where the Spinner is used.

Required actions:

1. Build codemod
2. Build test
3. Update readme with description & example