CI - CLI doc check shouldn't fail on Cargo.lock diff (#3739)

# Description of Changes

Stop the CLI doc check from failing on `Cargo.lock` diffs, which it was
doing before.

# API and ABI breaking changes

CI only.

# Expected complexity level and risk

1

# Testing

- [x] CI still fails elsewhere if `Cargo.lock` needs updating

---------

Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

Author: bfops

.github/workflows/ci.yml

@@ -512,7 +512,7 @@ jobs:
           cargo run --features markdown-docs -p spacetimedb-cli > docs/docs/cli-reference.md
           pnpm format
           git status
-          if git diff --exit-code HEAD; then
+          if git diff --exit-code HEAD -- docs/docs/cli-reference.md; then
             echo "No docs changes detected"
           else
             echo "It looks like the CLI docs have changed:"