Update tracing-subscriber requirement from 0.2 to 0.3 in /ruby/generator

Updates the requirements on [tracing-subscriber](https://github.com/tokio-rs/tracing) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/tracing/releases)
- [Commits](tokio-rs/tracing@tracing-subscriber-0.2.0...tracing-subscriber-0.3.0)

---
updated-dependencies:
- dependency-name: tracing-subscriber
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

ruby/generator/Cargo.toml

@@ -10,6 +10,6 @@ edition = "2018"
 clap = "2.33"
 node-types = { path = "../node-types" }
 tracing = "0.1"
-tracing-subscriber = { version = "0.2", features = ["env-filter"] }
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tree-sitter-embedded-template = "0.19"
 tree-sitter-ruby = { git = "https://github.com/tree-sitter/tree-sitter-ruby.git", rev = "bb6a42e42b048627a74a127d3e0184c1eef01de9" }