Cargo.toml,README.md: Bump version to 0.4.1

Bug fixes:

- Fix integer overflow in local function calls by using checked
  arithmetic for call offsets. Previously, certain call offset values
  could cause an integer overflow/underflow.
- Fix 32-bit ALU operations (ADD32, SUB32, MUL32) to properly
  zero-extend results. The result is now correctly cast to u32 before
  extending to u64.
- Replace unimplemented!() panics with proper error messages for
  unsupported instructions (XADD, TAIL_CALL), preventing unexpected
  panics during execution.
- In the x86_64 JIT compiler, fix divisor handling in emit_muldivmod:
  the JIT now correctly uses the is_reg flag to determine whether the
  divisor is in a register or an immediate value, rather than checking
  if imm != 0.

(These notes were mostly generated from the Git history by Claude Code.)

Signed-off-by: Quentin Monnet <qmo@qmon.net>

Author: qmonnet

Cargo.toml

@@ -2,7 +2,7 @@
 
 # Project metadata
 name = "rbpf"
-version = "0.4.0"
+version = "0.4.1"
 authors = ["Quentin Monnet <qmo@qmon.net>"]
 
 # Additional metadata for packaging

README.md

@@ -52,7 +52,7 @@ file:
 
 ```toml
 [dependencies]
-rbpf = "0.4.0"
+rbpf = "0.4.1"
 ```
 
 You can also use the development version from this GitHub repository. This
@@ -388,7 +388,7 @@ to your `Cargo.toml` file.
 
 ```toml
 [dependencies]
-rbpf = "0.4.0"
+rbpf = "0.4.1"
 elf = "0.8.0"
 ```
 
@@ -581,7 +581,7 @@ enabled-by-default features.
 
 ```toml
 [dependencies]
-rbpf = { version = "0.4.0", default-features = false }
+rbpf = { version = "0.4.1", default-features = false }
 ```
 
 Note that when using this crate in `no_std` environments, the `jit` module