feat: introduce process lock so that solo doesn't allow parallel execution of commands #129

All 83 tests pass in 25s

1 files ±0 13 suites ±0 25s ⏱️ -5s
83 tests ±0 83 ✅ ±0 0 💤 ±0 0 ❌ ±0
90 runs ±0 90 ✅ ±0 0 💤 ±0 0 ❌ ±0

Results for commit d5c6463. ± Comparison against earlier commit 72bace7.