Sidecar injector to discover patch releases of Dapr sidecar

## In what area(s)?

> /area runtime

/area operator

> /area placement

> /area docs

> /area test-and-release
## Describe the proposal

Today, the Sidecar Injector will always inject the same sidecar image, even if there is patch available. Since Dapr follows Semantic Versioning, it should be relative safe to inject a patched version of the sidecar for new Pods, even if it means fragmenting the cluster. It means that it should be safe to run all patch versions of 1.7.X in the same cluster. Also, most of the hotfixes are on the Dapr sidecar and not control plane.

This proposal is to add an optional setting in Sidecar Injector that will allow automatically discovery of new patches for the same minor version of the Dapr sidecar and use that in sidecar container of new Pods.

For example, this can enable a hotfix of the Dapr sidecar to be deployed by simply restarting the app's deployment.