feat: add --batch-size flag to push refs in batches (#173)

* feat: add --batch-size flag to push refs in batches

Add support for pushing refs in smaller batches to avoid server-side
limits and timeouts when syncing large repositories with many tags/branches.

- Add --batch-size flag (default 0 = no batching, original behavior)
- Add References() method to GitRepository interface
- Implement collectRefs() and pushRefsInBatches() helpers
- Add MinBatchSize validation (must be 0 or >= 10)

This addresses issues where repositories with 1000+ refs fail to sync
to GHES with 'command error on refs/heads/<branch>: failed' errors.

* test: add tests for batch-size flag and push batching functionality

* fix: pin tool dependencies to versions compatible with Go 1.21

* ci: fix docker compose v2 syntax and update setup-ruby action

* refactor: address PR review feedback

- Remove unused RefInfo struct from git.go
- Remove redundant pushedAny variable tracking in pushRefsInBatches
- Remove incomplete TestPushRefsInBatches_PartialUpToDate test (already covered by existing test case)

* docs: add --batch-size flag to README

.github/workflows/ci.yml

@@ -9,8 +9,8 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v4
     - name: Lint
-      run: docker-compose run --rm lint
+      run: docker compose run --rm lint
     - name: Test
-      run: docker-compose run --rm test
+      run: docker compose run --rm test
     - name: E2E
-      run: docker-compose run --rm test-build
+      run: docker compose run --rm test-build

.github/workflows/licensed.yml

@@ -35,7 +35,7 @@ jobs:
       - run: go mod vendor
 
       # Ruby is required for licensed
-      - uses: ruby/setup-ruby@6bd3d993c602f6b675728ebaecb2b569ff86e99b
+      - uses: ruby/setup-ruby@90be1154f987f4dc0fe0dd0feedac9e473aa4ba8 # v1
         with:
           ruby-version: "3.2"