fix: add missing license fields for cargo-deny audit

Adds `license = "CC0-1.0"` to `fuzz/Cargo.toml` and `rpc-integration-test/Cargo.toml` to pass cargo-deny license checks added in the CI overhaul PR #253.

Author: xdustinface

fuzz/Cargo.toml

@@ -3,6 +3,7 @@ name = "dash-fuzz"
 edition = "2024"
 version = { workspace = true}
 authors = ["Generated by fuzz/generate-files.sh"]
+license = "CC0-1.0"
 publish = false
 
 [profile.release]

rpc-integration-test/Cargo.toml

@@ -1,6 +1,7 @@
 [package]
 name = "integration_test"
 authors = ["Steven Roose <[email protected]>"]
+license = "CC0-1.0"
 edition = "2024"
 publish = false