fix: clippy byte_char_slices lint, Docker java artifact path

.dockerignore

@@ -5,6 +5,5 @@ target/
 *.md
 docs/
 crates/*/target/
-plugins/*/build/
 plugins/*/.gradle/
 plugins/.gradle/

.github/workflows/ci.yml

@@ -91,7 +91,6 @@ jobs:
       - uses: actions/download-artifact@v4
         with:
           name: rampart-java-plugins
-          path: plugins/
       - name: Build edge
         uses: docker/build-push-action@v6
         with:

crates/rampart-core/src/pow/verifier.rs

@@ -2,7 +2,7 @@ use crate::pow::challenge::Challenge;
 use sha2::{Digest, Sha256};
 use subtle::ConstantTimeEq;
 
-const ALLOWED: [u8; 4] = [b'0', b'1', b'2', b'3'];
+const ALLOWED: [u8; 4] = *b"0123";
 
 pub fn verify(challenge: &mut Challenge, nonce: &str) -> bool {
     if challenge.used {