Fetch docs version from changelog rather than tag

.backstage/get_version.cjs

@@ -0,0 +1,29 @@
+const fs = require("fs");
+const path = require("path");
+
+const changelogFile = path.join(__dirname, "../CHANGELOG.md");
+
+const err = (m) => {
+    console.error(m);
+    process.exit(1);
+}
+
+if (!fs.existsSync(changelogFile)) err(`Script expected a file at ${changelogFile}`);
+
+let contents = fs.readFileSync(changelogFile, { encoding: "utf-8" });
+let version = "", lines = contents.split(/\n/g);
+let it = lines.entries();
+
+while (!(entry = it.next()).done) {
+    let [, line] = entry.value;
+    // Read until we reach the section for the latest version.
+    if (/^\s*##\s+v/i.test(line)) {
+        version = line.match(/^\s*##\s+(v\S+)/)[1];
+        if (version) {
+            console.log(version);
+            process.exit(0);
+        }
+    }
+}
+
+err("No version found in changelog");

.cloudcannon/prebuild

@@ -1,2 +1,2 @@
-export HUGO_PAGEFIND_DOCS_VERSION=$(git describe --tags --abbrev=0)
+export HUGO_PAGEFIND_DOCS_VERSION=$(node ./.backstage/get_version.cjs)
 echo "Building documentation for $HUGO_PAGEFIND_DOCS_VERSION"