fix smallvec for nightly

Author: ModProg

CHANGELOG.md

@@ -4,7 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-<!-- ## [Unreleased] -->
+## [Unreleased]
+### Fixed
+- bumped `smallvec` version to `1.5` to avoid nightly feature compilation issues.
 
 ## [0.7.0] - 2023-05-14
 - Increased documentation and test coverage.

Cargo.toml

@@ -15,7 +15,7 @@ include = ["src/**/*", "LICENSE-*", "README.md", "CHANGELOG.md"]
 [dependencies]
 proc-macro2 = { version = "1", optional = true }
 quote = { version = "1", optional = true }
-smallvec = { version = "1.4", optional = true, features = ["const_generics"] }
+smallvec = { version = "1.5", optional = true, features = ["const_generics"] }
 
 [features]
 default = ["proc-macro2", "proc-macro", "parser", "quote"]