travis: return cp task removed accidentally

.travis.yml

@@ -43,7 +43,7 @@ script:
   - BUILD_DUMMY_WASM_BINARY=0 WASM_BUILD_TOOLCHAIN=nightly-2020-05-23 cargo build --release --target=${TARGET}
 
 before_deploy:
-
+  - cp ./target/${TARGET}/release/joystream-node .
   - FILENAME=`./joystream-node --version | sed -e "s/ /-/g"`
   - tar -cf ${FILENAME}.tar ./joystream-node
   - gzip ${FILENAME}.tar