Include ReScript commit hash in version string.

Author: cknitt

bin/Version.re

@@ -1 +1,3 @@
-let version = "0.9.1";
+// *** GENERATED BY "yarn setVersion" ***
+
+let version = "0.9.1 (ReScript 7cc70c9)";

scripts/setVersion.js

@@ -1,6 +1,24 @@
 const fs = require("fs");
-const { version } = require("../package.json");
+const child_process = require("child_process");
 
-fs.writeFileSync("bin/Version.re", `let version = "${version}";\n`);
+const packageJson = fs.readFileSync("package.json");
+const packageVersion = JSON.parse(packageJson).version;
+
+const reScriptVersion = child_process
+  .execSync(`git submodule`)
+  .toString()
+  .trim()
+  .split(" ")[0]
+  .substr(0, 7);
+
+const version = `${packageVersion} (ReScript ${reScriptVersion})`;
+
+fs.writeFileSync(
+  "bin/Version.re",
+  `// *** GENERATED BY "yarn setVersion" ***
+
+let version = "${version}";
+`
+);
 
 console.log(`Version set to ${version}`);