Explicitly fetch main branch

Author: rameel

.github/scripts/compare-packages-size.js

@@ -37,6 +37,7 @@ function icon(d) {
 const pr_files = glob("dist/**/*.min.js");
 const pr_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
 
+exec("git fetch origin main", { stdio: "inherit" });
 exec("git checkout origin/main", { stdio: "ignore" });
 exec("npm ci", { stdio: "inherit" });
 exec("npm run build", { stdio: "inherit" });