adoptopenjdk-bin: write new line according to .editorconfig

pkgs/development/compilers/adoptopenjdk-bin/generate-sources.py

@@ -63,3 +63,4 @@ for release in releases:
 
 with open("sources.json", "w") as f:
     json.dump(out, f, indent=2, sort_keys=True)
+    f.write('\n')

pkgs/development/compilers/adoptopenjdk-bin/sources.json

@@ -673,4 +673,4 @@
       }
     }
   }
-}
+}