README: add zstd to dependency list

bgilbert · bgilbert · commit 05bf232c01c4 · 2024-05-21T01:13:56.000-05:00
Signed-off-by: Benjamin Gilbert &lt;bgilbert@cs.cmu.edu&gt;
diff --git a/README.md b/README.md
@@ -76,6 +76,7 @@ To build OpenSlide, you will need:
 - OpenJPEG ≥ 2.1
 - SQLite ≥ 3.14
 - zlib
+- Zstandard
 
 Then:
 
