Eliminate warnings, add clippy+cargo-audit to CI, add fuzz target

fuzz/fuzz_targets/parse_gvas.rs

@@ -0,0 +1,7 @@
+#[fuzz]
+mod target {
+    #[fuzz]
+    fn parse_gvas(data: &[u8]) {
+        let _ = notalterra::gvas::extract_metadata_from_bytes(data);
+    }
+}