docs(README): remove redundant notes on runtime dependencies

Author: mrz1836

README.md

@@ -128,9 +128,6 @@ go get -u github.com/bsv-blockchain/go-subtree
 - **Benchmarks** – Check the latest numbers in the [benchmark results](#benchmark-results)
 - **Test Suite** – Review both the [unit tests](subtree_test.go) and [fuzz tests](subtree_fuzz_test.go) (powered by [`testify`](https://github.com/stretchr/testify))
 
-> **Good to know:** `go-subtree` ships with *zero* runtime dependencies.
-> The only external package we use is `testify`—and that's strictly for tests.
-
 <br/>
 
 <details>