v1.0.1

• Bump go version to v1.20
• Bump cert-manager package to support version of Kubernetes from v1.22-v1.27. Current version of cert-manager packages is v1.12LTS
• Change two copy directives in Dockerfile to just one
• Change up a old generic version of main_test.go to new generic version of main_test.go
• Update README.md with supported Kubernetes versions and minor cosmetic adjustments

Full Changelog: v1.0.0...v1.0.1