Add support for LLVM 20

[clin1234]

Because the version of llvm-sys is 180.0.0 when installing via cargo, it is not compatible with the default version of LLVM provided in Fedora Rawhide, which is 20. This yields the following error:

error: No suitable version of LLVM was found system-wide or pointed
              to by LLVM_SYS_180_PREFIX.
       
              Consider using `llvmenv` to compile an appropriate copy of LLVM, and
              refer to the llvm-sys documentation for more information.
       
              llvm-sys: https://crates.io/crates/llvm-sys
              llvmenv: https://crates.io/crates/llvmenv
   --> /home/cc/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/llvm-sys-180.0.0/src/lib.rs:515:1
    |
515 | / std::compile_error!(concat!(
516 | |     "No suitable version of LLVM was found system-wide or pointed
517 | |        to by LLVM_SYS_",
518 | |     env!("CARGO_PKG_VERSION_MAJOR"),
...   |
525 | |        llvmenv: https://crates.io/crates/llvmenv"
526 | | ));
    | |__^

error: could not compile `llvm-sys` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: failed to compile `llql v0.5.0`, intermediate artifacts can be found at `/tmp/cargo-installt6ppBZ`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_TARGET_DIR` to that path.
ERROR Cargo errored! ExitStatus(unix_wait_status(25856))
ERROR Fatal error:
  × For crate llql: subprocess /home/cc/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo install llql
  │ --version 0.5.0 --force --root /home/cc/.cargo errored with exit status: 101
  ╰─▶ subprocess /home/cc/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo install llql --version 0.5.0
      --force --root /home/cc/.cargo errored with exit status: 101

[AmrDeveloper]

Hello @clin1234,

Thank you for your suggestion I will migrate to 19 then 20 soon

Thank you,
Amr