Merge rust-bitcoin/rust-bitcoin#2700: Fix kani test

e47e57c265 Fix kani test (Tobin C. Harding)

Pull request description:

  In a kani test we are checking if the result of `to_unsigned()` is an error but setting `is_signed` to `true`, this field represents the signed-ness of the return type of `to_unsigned` (`Amount`) so should be `false`.

  Fix kani daily job.

ACKs for top commit:
  apoelstra:
    ACK e47e57c265

Tree-SHA512: b0b4ace6d66dbbd30df3da1cbc233bfa994e7e003e049e949af4ab03b01c09d0cc29fd40d84a93a7d41e94751da91407e391c80d3de7064e9ac23485273309a6

units/src/amount.rs

@@ -1973,7 +1973,7 @@ mod verification {
             if n1 >= 0 {
                 Ok(Amount::from_sat(n1.try_into().unwrap()))
             } else {
-                Err(OutOfRangeError { is_signed: true, is_greater_than_max: false })
+                Err(OutOfRangeError { is_signed: false, is_greater_than_max: false })
             },
         );
     }