Extend build-cross target with riscv64 arch

Signed-off-by: Michal Biesek <[email protected]>

Author: michalbiesek

Makefile

@@ -18,6 +18,7 @@ build-cross:
 	$(call go-build,linux,ppc64le)
 	$(call go-build,linux,s390x)
 	$(call go-build,linux,mips64le)
+	$(call go-build,linux,riscv64)
 	$(call go-build,windows,amd64)
 	$(call go-build,windows,386)