Fixed tests that are failing in Rust 1.63

- Rust version 1.63 changed how they convert float to Durations. Previously they truncated, now they round
  - https://github.com/rust-lang/rust/releases/tag/1.63.0
  - rust-lang/rust#96051
  - 'Rounding is now used when converting a float to a Duration. The converted duration can differ slightly from what it was.'

lib/mod_interval/src/lib.rs

@@ -406,6 +406,10 @@ mod tests {
         }
     }
 
+    // https://github.com/rust-lang/rust/releases/tag/1.63.0
+    // Compatibility Notes
+    // Rounding is now used when converting a float to a Duration. The converted duration can differ slightly from what it was.
+    // https://github.com/rust-lang/rust/pull/96051/
     #[test]
     fn single_segment() {
         // start perx, duration, end perx