chore: checkpoint before Python removal

vendor/tiny-keccak/examples/sha3.rs

@@ -0,0 +1,17 @@
+use tiny_keccak::{Hasher, Sha3};
+
+fn main() {
+    let mut sha3 = Sha3::v256();
+    let mut output = [0; 32];
+    let expected = b"\
+        \x64\x4b\xcc\x7e\x56\x43\x73\x04\x09\x99\xaa\xc8\x9e\x76\x22\xf3\
+        \xca\x71\xfb\xa1\xd9\x72\xfd\x94\xa3\x1c\x3b\xfb\xf2\x4e\x39\x38\
+    ";
+
+    sha3.update(b"hello");
+    sha3.update(b" ");
+    sha3.update(b"world");
+    sha3.finalize(&mut output);
+
+    assert_eq!(expected, &output);
+}