cli/config/configfile: deprecate ConfigFile.Experimental field

Configuration options for experimental CLI features were deprecated in
docker 19.03 (3172219), and enabled by
default since docker 20.10 (977d3ae).

This deprecates the corresponding field in the config-file.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

cli/config/configfile/file.go

@@ -36,12 +36,14 @@ type ConfigFile struct {
 	NodesFormat          string                       `json:"nodesFormat,omitempty"`
 	PruneFilters         []string                     `json:"pruneFilters,omitempty"`
 	Proxies              map[string]ProxyConfig       `json:"proxies,omitempty"`
-	Experimental         string                       `json:"experimental,omitempty"`
 	CurrentContext       string                       `json:"currentContext,omitempty"`
 	CLIPluginsExtraDirs  []string                     `json:"cliPluginsExtraDirs,omitempty"`
 	Plugins              map[string]map[string]string `json:"plugins,omitempty"`
 	Aliases              map[string]string            `json:"aliases,omitempty"`
 	Features             map[string]string            `json:"features,omitempty"`
+
+	// Deprecated: experimental CLI features are always enabled and this field is no longer used. Use [Features] instead for optional features. This field will be removed in a future release.
+	Experimental string `json:"experimental,omitempty"`
 }
 
 // ProxyConfig contains proxy configuration settings