feat(comp): Add descriptions for --version comp

Ref: HIP 0008

When completing a version, extra information will be shown for
shells that support completions (fish, zsh).  For example:

$ helm upgrade nginx stable/grafana --version <TAB>
0.8.4   -- Created: March 30, 2018
0.8.5   -- App: 5.0.4, Created: April 10, 2018
1.0.0   -- App: 5.0.4, Created: April 11, 2018 (deprecated)
1.10.0  -- App: 5.1.2, Created: June 1, 2018

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

cmd/helm/flags.go

@@ -150,7 +150,21 @@ func compVersionFlag(chartRef string, toComplete string) ([]string, cobra.ShellC
 		for _, details := range indexFile.Entries[chartName] {
 			version := details.Metadata.Version
 			if strings.HasPrefix(version, toComplete) {
-				versions = append(versions, version)
+				appVersion := details.Metadata.AppVersion
+				appVersionDesc := ""
+				if appVersion != "" {
+					appVersionDesc = fmt.Sprintf("App: %s, ", appVersion)
+				}
+				created := details.Created.Format("January 2, 2006")
+				createdDesc := ""
+				if created != "" {
+					createdDesc = fmt.Sprintf("Created: %s ", created)
+				}
+				deprecated := ""
+				if details.Metadata.Deprecated {
+					deprecated = "(deprecated)"
+				}
+				versions = append(versions, fmt.Sprintf("%s\t%s%s%s", version, appVersionDesc, createdDesc, deprecated))
 			}
 		}
 	}

cmd/helm/testdata/helmhome/helm/repository/testing-index.yaml

@@ -4,6 +4,8 @@ entries:
     - name: alpine
       url: https://charts.helm.sh/stable/alpine-0.1.0.tgz
       checksum: 0e6661f193211d7a5206918d42f5c2a9470b737d
+      created: "2018-06-27T10:00:18.230700509Z"
+      deprecated: true
       home: https://helm.sh/helm
       sources:
         - https://github.com/helm/helm
@@ -17,6 +19,7 @@ entries:
     - name: alpine
       url: https://charts.helm.sh/stable/alpine-0.2.0.tgz
       checksum: 0e6661f193211d7a5206918d42f5c2a9470b737d
+      created: "2018-07-09T11:34:37.797864902Z"
       home: https://helm.sh/helm
       sources:
         - https://github.com/helm/helm
@@ -30,6 +33,7 @@ entries:
     - name: alpine
       url: https://charts.helm.sh/stable/alpine-0.3.0-rc.1.tgz
       checksum: 0e6661f193211d7a5206918d42f5c2a9470b737d
+      created: "2020-11-12T08:44:58.872726222Z"
       home: https://helm.sh/helm
       sources:
         - https://github.com/helm/helm
@@ -44,6 +48,7 @@ entries:
     - name: mariadb
       url: https://charts.helm.sh/stable/mariadb-0.3.0.tgz
       checksum: 65229f6de44a2be9f215d11dbff311673fc8ba56
+      created: "2018-04-23T08:20:27.160959131Z"
       home: https://mariadb.org
       sources:
         - https://github.com/bitnami/bitnami-docker-mariadb

cmd/helm/testdata/output/version-comp.txt

@@ -1,5 +1,5 @@
-0.3.0-rc.1
+0.3.0-rc.1	App: 3.0.0, Created: November 12, 2020
-0.2.0
+0.2.0	App: 2.3.4, Created: July 9, 2018
-0.1.0
+0.1.0	App: 1.2.3, Created: June 27, 2018 (deprecated)
 :4
 Completion ended with directive: ShellCompDirectiveNoFileComp