fix: fetch depth in main action incorrect (#47)

fetch depth should be lookback (10) + 1

also, re-enable prune because it's a public repo

.github/workflows/find-code-refs.yml

@@ -13,7 +13,7 @@ jobs:
  - uses: actions/checkout@v4
  with:
  repository: launchdarkly/SupportService
- fetch-depth: 10
+ fetch-depth: 11
  - name: LaunchDarkly Code References
  uses: launchdarkly/find-code-references@main
  with:
@@ -22,3 +22,4 @@ jobs:
  ignoreServiceErrors: true
  projKey: support-service
  allowTags: true
+ prune: true