Add missing Requires

Turns out BuildRequires don't translate to Requires automatically (not
in this dirty setup, anyway).  Nasty as is, we have to add them by hand.
Yes, even devel.

Sorry I didn't know better, Java guys!

bisq-exchange.spec.in

 BuildRequires: java-1.8.0-openjdk-openjfx
 BuildRequires: maven
 
+Requires: java-1.8.0-openjdk-devel
+Requires: java-1.8.0-openjdk-openjfx
 %description
 The decentralized bitcoin exchange https://bisq.network