Add ghcr.io to list of registries without nested support (#61)

* Add ghcr.io to list of registries without nested support

Closes #60

* Add GHCR to README and fix gofmt

Author: mnasiadka

README.md

@@ -74,7 +74,7 @@ If the `target` registry does _not_ support nested paths, only the base path of
 mycompany.com/myteam/prometheus-operator:v0.40.0
 ```
 
-**Registries that do not support nested paths:** Docker Hub, Quay.io
+**Registries that do not support nested paths:** Docker Hub, GitHub Container Registry, Quay.io
 
 ## Usage
 

internal/manifest/manifest.go

@@ -366,6 +366,11 @@ func hostSupportsNestedRepositories(host string) bool {
 		return false
 	}
 
+	// GHCR.io
+	if strings.Contains(host, "ghcr.io") {
+		return false
+	}
+
 	// Docker Registry (Docker Hub)
 	// An empty host is assumed to be Docker Hub.
 	if strings.Contains(host, "docker.io") || host == "" {