Set default log level when not using RUST_LOG

[darrell-roberts]

The logger would not initialize unless RUST_LOG was defined.

Fixed this to use default to info and allow RUST_LOG override.

Fixes: #197

Example of parsing errors with change:

[2024-11-12 17:34:16.825715 -05:00] INFO [typeshare] cli/src/main.rs:48: typeshare started generating types
[2024-11-12 17:34:18.855152 -05:00] ERROR [typeshare] cli/src/main.rs:269: Parsing error: "the serde tag attribute is not supported for non-algebraic enums: SomeBadEnum" in file "/Users/darrellroberts/projects/my-proj/src/types.rs"
[2024-11-12 17:34:18.855216 -05:00] ERROR [typeshare] cli/src/main.rs:269: Parsing error: "the serde tag attribute is not supported for non-algebraic enums: AnotherBadEnum" in file "/Users/darrellroberts/projects/my-proj/src/types.rs"
[2024-11-12 17:34:18.855230 -05:00] ERROR [typeshare] cli/src/main.rs:269: Parsing error: "the serde tag attribute is not supported for non-algebraic enums: SomeBadEnum" in file "/Users/darrellroberts/projects/my-proj/src/types.rs"
[2024-11-12 17:34:18.855238 -05:00] ERROR [typeshare] cli/src/main.rs:269: Parsing error: "the serde tag attribute is not supported for non-algebraic enums: AnotherBadEnum" in file "/Users/darrellroberts/projects/my-proj/src/types.rs"
[2024-11-12 17:34:18.855252 -05:00] ERROR [typeshare] cli/src/main.rs:277: Errors encountered during parsing.
Error: Errors encountered during parsing.