fix(canary): use heredoc for node script to avoid shell quoting issues

The double-quoted node -e broke on the \" inside the JS string.
Heredoc avoids all shell quoting problems.

.github/workflows/canary.yml

@@ -111,7 +111,7 @@ jobs:
           # create a minimal one. `changeset version --snapshot` consumes and
           # deletes it, so no cleanup is needed.
           if [ -z "$(ls .changeset/*.md 2>/dev/null | grep -vi 'README')" ]; then
-            node -e "
+            node << 'SCRIPT'
               const cfg = require('./.changeset/config.json');
               const pkgs = cfg.linked.flat();
               let body = '---
@@ -123,7 +123,7 @@ jobs:
 chore: canary build
 ';
               require('fs').writeFileSync('.changeset/canary-temp.md', body);
-            "
+            SCRIPT
           fi
           pnpm changeset version --snapshot nightly
         env: