adds fix to build errors

[saad039]

Upon building dex using the command cargo build-bpf --manifest-path=./Cargo.toml --bpf-out-dir=dist, I get the error

error[E0107]: this struct takes 0 lifetime arguments but 1 lifetime argument was supplied
   --> src/lib.rs:375:20
    |
375 |     StdoutLock(io::StdoutLock<'a>),
    |                    ^^^^^^^^^^---- help: remove these generics
    |                    |
    |                    expected 0 lifetime arguments

error[E0107]: this struct takes 0 lifetime arguments but 1 lifetime argument was supplied
   --> src/lib.rs:376:20
    |
376 |     StderrLock(io::StderrLock<'a>),
    |                    ^^^^^^^^^^---- help: remove these generics
    |                    |
    |                    expected 0 lifetime arguments

For more information about this error, try `rustc --explain E0107`.
error: could not compile `termcolor` due to 2 previous errors
warning: build failed, waiting for other jobs to finish...
error: build failed

This is fixed by bumping up the solana-program version from 1.6.18 to 1.11