fix: Specify minimum rust version

Unsigned `is_multiple_of` used in `serde_primitives::decode_hex_with_prefix()` is stabilized only in `1.87` version of rust as per this issue rust-lang/rust#137383
Building the package with older version fails

Author: pistomat

tycho-common/Cargo.toml

@@ -10,7 +10,7 @@ keywords.workspace = true
 license.workspace = true
 categories.workspace = true
 readme = "README.md"
-
+rust-version = "1.87.0"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html