Update libloading requirement from 0.8 to 0.9 (#710)

Updates the requirements on [libloading](https://github.com/nagisa/rust_libloading) to permit the latest version.
- [Commits](nagisa/rust_libloading@0.8.0...0.9.0)

---
updated-dependencies:
- dependency-name: libloading
  dependency-version: 0.9.0
  dependency-type: direct:production
...

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Author: dependabot[bot]

rustler/Cargo.toml

@@ -27,7 +27,7 @@ num-bigint = { version = "0.4", optional = true }
 serde = { version = "1", optional = true }
 
 [target.'cfg(not(windows))'.dependencies]
-libloading = "0.8"
+libloading = "0.9"
 
 [build-dependencies]
 regex-lite = "0.1"