Update SDK to 1.21.0

[jsullivan-CS]

Expected changes to update SDK to 1.21.0; would like to verify with a current maintainer.

[redhatrises]

A couple of additional things:

1. Can you remove the falcon-operator binary file
2. Also, looks like the metadata is missing the relatedImages content. e.g.

   +  relatedImages:
   +  - image: "" 
   +    name: node-sensor
   

[redhatrises]

Also, reading the 1.21 release notes, it seems like the following changes were missed:

1. https://sdk.operatorframework.io/docs/upgrading-sdk-version/v1.21.0/#for-golanghelmansible-based-operators-upgrade-kube-rbac-proxy-image-from-v080-to-v0110-for-further-information-see-the-kube-rbac-proxy-release-noteshttpsgithubcombranczkube-rbac-proxyreleases
2. https://sdk.operatorframework.io/docs/upgrading-sdk-version/v1.21.0/#for-golang-based-operators--change-makefile-targets-to-replace-go-get-with-go-install

If you can, add them to this PR, please. Or if you want, I can create a follow up PR to this one with the necessary changes.

Thanks for opening this PR!

[jsullivan-CS]

Also, reading the 1.21 release notes, it seems like the following changes were missed:

1. https://sdk.operatorframework.io/docs/upgrading-sdk-version/v1.21.0/#for-golanghelmansible-based-operators-upgrade-kube-rbac-proxy-image-from-v080-to-v0110-for-further-information-see-the-kube-rbac-proxy-release-noteshttpsgithubcombranczkube-rbac-proxyreleases
2. https://sdk.operatorframework.io/docs/upgrading-sdk-version/v1.21.0/#for-golang-based-operators--change-makefile-targets-to-replace-go-get-with-go-install

If you can, add them to this PR, please. Or if you want, I can create a follow up PR to this one with the necessary changes.

Thanks for opening this PR!

🙇 Thanks very much for the feedback; changes included in the most recent commit update.