relup: Don't insist on specifying release name/version

[weiss]

Environment

Rebar3 3.22.0 on Erlang/OTP 26.0.2.

Current behaviour

The following example works fine, but it would be nice if the final rebar3 relup command wouldn't insist on having the release name and version specified on the command line:

rebar3 new release example
cd example
sed -i '/{mode,/d' rebar.config
echo '{plugins, [rebar3_appup_plugin]}.' >> rebar.config
rebar3 release
sed -i 's/intensity => 0/intensity => 1/' apps/example/src/example_sup.erl
sed -i 's/0.1.0/0.2.0/' rebar.config apps/example/src/example.app.src
rebar3 release
rebar3 appup generate
rebar3 relup -n example -v 0.2.0

Expected behaviour

By default, rebar3 relup should choose the same release name/version as rebar3 release.