Add check version functionality (#296)

* Add check version functionality
 * add backend support
 * add ui support
 * minor fixes
 * cosmetic fixes
 * workaround query refetch not working after network error
 * revert changes to Makefile after testing is complete
 * switch to Releases Github API endpoint, add latest Release URL to UI
 * latest version is only shown in UI when version is available and data is ready
 * resolve conflict , squash rebase

pkg/api/resolver.go

@@ -6,7 +6,7 @@ import (
 	"strconv"
 
 	"github.com/99designs/gqlgen/graphql"
-
+	"github.com/stashapp/stash/pkg/logger"
 	"github.com/stashapp/stash/pkg/models"
 )
 
@@ -116,6 +116,21 @@ func (r *queryResolver) Version(ctx context.Context) (*models.Version, error) {
 	}, nil
 }
 
+//Gets latest version (git shorthash commit for now)
+func (r *queryResolver) Latestversion(ctx context.Context) (*models.ShortVersion, error) {
+	ver, url, err := GetLatestVersion(true)
+	if err == nil {
+		logger.Infof("Retrieved latest hash: %s", ver)
+	} else {
+		logger.Errorf("Error while retrieving latest hash: %s", err)
+	}
+
+	return &models.ShortVersion{
+		Shorthash: ver,
+		URL:       url,
+	}, err
+}
+
 // Get scene marker tags which show up under the video.
 func (r *queryResolver) SceneMarkerTags(ctx context.Context, scene_id string) ([]*models.SceneMarkerTag, error) {
 	sceneID, _ := strconv.Atoi(scene_id)