Merge #731: fix: possible absolute locktime overflow error

d01ad3f fix: possible absolute locktime overflow error (Chris Hyunhum Cho)

Pull request description:

  Maximum absolute locktime is 2^31 - 1, not 2^31 in miniscript.

  reference: https://github.com/bitcoin/bitcoin/blob/master/src/script/miniscript.h#L2281

ACKs for top commit:
  apoelstra:
    ACK d01ad3f successfully ran local tests

Tree-SHA512: cde3ea0b0ed4cfc4b30cc8ff3b2da33241581a5ea55849e61d17d7b2788028e666dd7047be5450dc73a14dba25f52b982da8eae6818902439cd1f5b892730bb9

src/primitives/absolute_locktime.rs

@@ -7,7 +7,7 @@ use core::{cmp, fmt};
 use bitcoin::absolute;
 
 /// Maximum allowed absolute locktime value.
-pub const MAX_ABSOLUTE_LOCKTIME: u32 = 0x8000_0000;
+pub const MAX_ABSOLUTE_LOCKTIME: u32 = 0x7FFF_FFFF;
 
 /// Minimum allowed absolute locktime value.
 ///