Add SHA256

Author: rossberg

packages/wasm/wasm.2.0.2/opam

@@ -19,5 +19,8 @@ install: [make "-C" "interpreter" "install"]
 dev-repo: "git+https://github.com/WebAssembly/spec.git"
 url {
   src: "https://github.com/WebAssembly/spec/archive/opam-2.0.2.zip"
-  checksum: "md5=ae81b4432ab5fa5c0af156926c9ca781"
+  checksum: [
+    "md5=ae81b4432ab5fa5c0af156926c9ca781"
+    "sha256=ff3ccdc7b76eead5d9d9ab6ec365ba87541416d023c0235c10eb2f7975483f66"
+  ]
 }