Update README.md

Author: charlesgonzales

guava/README.md

@@ -17,3 +17,5 @@
 - [Using Guava CountingOutputStream](http://www.baeldung.com/guava-counting-outputstream)
 - [Hamcrest Text Matchers](http://www.baeldung.com/hamcrest-text-matchers)
 - [Quick Guide to the Guava RateLimiter](http://www.baeldung.com/guava-rate-limiter)
+- [Hamcrest File Matchers](https://www.baeldung.com/hamcrest-file-matchers)
+- [SHA-256 Hashing in Java](https://www.baeldung.com/sha-256-hashing-java)