demo-protobuf: Fix type of demo.proto

packages/demo-protobuf/src/demo.proto.ts

@@ -1,4 +1,6 @@
-export default `
+// Without this TS infers this is a string literal.
+// eslint-disable-next-line @typescript-eslint/no-inferrable-types
+const proto: string = `
 syntax = "proto3";
 package demo;
 
@@ -6,3 +8,5 @@ message MsgDemo {
   string example = 1;
 }
 `;
+
+export default proto;

packages/demo-protobuf/types/demo.proto.d.ts

@@ -1,2 +1,2 @@
-declare const _default: '\nsyntax = "proto3";\npackage demo;\n\nmessage MsgDemo {\n  string example = 1;\n}\n';
-export default _default;
+declare const proto: string;
+export default proto;