ci: fetch changeset base branch when snapshot (#12508)

* ci: fetch changeset base branch

* Update .github/workflows/snapshot-release.yml

Co-authored-by: Bjorn Lu <[email protected]>

* Remove redundant changeset pre exit command

* Fix indentation in snapshot-release workflow

---------

Co-authored-by: Bjorn Lu <[email protected]>

Author: ascorbic

.github/workflows/snapshot-release.yml

@@ -63,7 +63,13 @@ jobs:
           ref: ${{ steps.refs.outputs.head_ref }}
           fetch-depth: 0
 
-      - run: git fetch origin main:main
+      - name: Extract base branch from .changeset/config.json
+        id: getBaseBranch
+        run: |
+          baseBranch=$(jq -r '.baseBranch' .changeset/config.json)
+          echo "baseBranch=${baseBranch}" >> $GITHUB_OUTPUT
+
+      - run: git fetch origin ${{ steps.getBaseBranch.outputs.baseBranch }}:${{ steps.getBaseBranch.outputs.baseBranch }}
 
       - name: Setup PNPM
         uses: pnpm/action-setup@v3