moved all RE_USERNAME occurrences to regex.rs

switch to normal Cargo.toml

switch to normal Cargo.toml

switch to normal Cargo.toml

solved bug

src/util/mod.rs

@@ -1,3 +1,4 @@
 pub mod result;
 pub mod variables;
 pub mod ratelimit;
+pub mod regex;

src/util/regex.rs

@@ -0,0 +1,4 @@
+use once_cell::sync::Lazy;
+use regex::Regex;
+
+pub static RE_USERNAME: Lazy<Regex> = Lazy::new(|| Regex::new(r"^[a-zA-Z0-9_.]+$").unwrap());