MSRV bump for next_multiple_of in ruzstd.

Author: khuey

.github/workflows/main.yml

@@ -265,7 +265,7 @@ jobs:
         with:
           submodules: true
       - name: Install Rust
-        run: rustup update 1.65.0 --no-self-update && rustup default 1.65.0
+        run: rustup update 1.73.0 --no-self-update && rustup default 1.73.0
       - run: cargo build
 
   miri: