github-ci: update Rust 1.91 for clippy and "known" stable

.github/workflows/builds.yml

@@ -35,7 +35,7 @@ env:
   # A recent version of stable Rust that is known to pass build, test and other
   # verification steps in this workflow. This was added because using "stable"
   # could cause some steps to fail.
-  RUST_VERSION_KNOWN: "1.90.0"
+  RUST_VERSION_KNOWN: "1.91.0"
 
 jobs:
 

.github/workflows/rust.yml

@@ -61,7 +61,7 @@ jobs:
                 sudo \
                 which \
                 zlib-devel
-      - run: curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain 1.90.0 -y
+      - run: curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain 1.91.0 -y
       - run: echo "$HOME/.cargo/bin" >> $GITHUB_PATH
       - run: cargo install bindgen-cli --version 0.66.0
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8