app: Add an update → upgrade alias

Same as `dnf` for example, and `flatpak` today uses `update`, so
let's do both.

Closes: https://github.com/projectatomic/rpm-ostree/issues/1448

Closes: #1449
Approved by: jlebon

src/app/main.c

@@ -62,6 +62,9 @@ static RpmOstreeCommand commands[] = {
   { "upgrade", RPM_OSTREE_BUILTIN_FLAG_SUPPORTS_PKG_INSTALLS,
     "Perform a system upgrade",
     rpmostree_builtin_upgrade },
+  { "update", RPM_OSTREE_BUILTIN_FLAG_SUPPORTS_PKG_INSTALLS | RPM_OSTREE_BUILTIN_FLAG_HIDDEN,
+    "Alias for upgrade",
+    rpmostree_builtin_upgrade },
   { "reload", 0,
     "Reload configuration",
     rpmostree_builtin_reload },

tests/vmcheck/test-upgrades.sh

@@ -29,6 +29,9 @@ vm_ostreeupdate_prepare_reboot
 
 # Test base ostree update
 vm_ostreeupdate_create v2
+# Test the update → upgrade alias
+vm_rpmostree update --check
+# Then use the real command
 vm_rpmostree upgrade
 vm_reboot
 vm_start_httpd ostree_server $REMOTE_OSTREE 8888