Update actions-rust-lang/setup-rust-toolchain action to v1.15.4

Author: renovate[bot]

.github/workflows/test.yml

@@ -124,7 +124,7 @@ jobs:
 
       - name: Set up rust toolchain
         if: matrix.package == 'stellar' && matrix.variant == 'compile'
-        uses: actions-rust-lang/setup-rust-toolchain@1780873c7b576612439a134613cc4cc74ce5538c # v1.15.2
+        uses: actions-rust-lang/setup-rust-toolchain@150fca883cd4034361b621bd4e6a9d34e5143606 # v1.15.4
         with:
           toolchain: stable, nightly
           components: clippy, rustfmt, llvm-tools-preview